diff --git a/backend/src/main/java/pdl/backend/Dao.java b/backend/src/main/java/pdl/backend/Dao.java
index 4c4ae7c..b3c6d6e 100644
--- a/backend/src/main/java/pdl/backend/Dao.java
+++ b/backend/src/main/java/pdl/backend/Dao.java
@@ -4,14 +4,14 @@ import java.util.Optional;
 import java.util.List;
 
 public interface Dao<T> {
-  
-  void create(final T t);
 
-  Optional<T> retrieve(final long id);
+	void create(final T t);
 
-  List<T> retrieveAll();
+	Optional<T> retrieve(final long id);
 
-  void update(final T t, final String[] params);
+	List<T> retrieveAll();
 
-  void delete(final T t);
+	void update(final T t, final String[] params);
+
+	void delete(final T t);
 }
diff --git a/backend/src/main/java/pdl/backend/Image.java b/backend/src/main/java/pdl/backend/Image.java
index 130e0ec..b5ea8ba 100644
--- a/backend/src/main/java/pdl/backend/Image.java
+++ b/backend/src/main/java/pdl/backend/Image.java
@@ -1,30 +1,30 @@
 package pdl.backend;
 
 public class Image {
-  private static Long count = Long.valueOf(0);
-  private Long id;
-  private String name;
-  private byte[] data;
+	private static Long count = Long.valueOf(0);
+	private Long id;
+	private String name;
+	private byte[] data;
 
-  public Image(final String name, final byte[] data) {
-    id = count++;
-    this.name = name;
-    this.data = data;
-  }
+	public Image(final String name, final byte[] data) {
+		id = count++;
+		this.name = name;
+		this.data = data;
+	}
 
-  public long getId() {
-    return id;
-  }
+	public long getId() {
+		return id;
+	}
 
-  public String getName() {
-    return name;
-  }
+	public String getName() {
+		return name;
+	}
 
-  public void setName(final String name) {
-    this.name = name;
-  }
+	public void setName(final String name) {
+		this.name = name;
+	}
 
-  public byte[] getData() {
-    return data;
-  }
+	public byte[] getData() {
+		return data;
+	}
 }
diff --git a/backend/src/main/java/pdl/backend/ImageController.java b/backend/src/main/java/pdl/backend/ImageController.java
index 6c38402..1e4962d 100644
--- a/backend/src/main/java/pdl/backend/ImageController.java
+++ b/backend/src/main/java/pdl/backend/ImageController.java
@@ -27,68 +27,68 @@ import org.springframework.web.servlet.mvc.support.RedirectAttributes;
 @RestController
 public class ImageController {
 
-  @Autowired
-  private ObjectMapper mapper;
+	@Autowired
+	private ObjectMapper mapper;
 
-  private final ImageDao imageDao;
+	private final ImageDao imageDao;
 
-  @Autowired
-  public ImageController(ImageDao imageDao) {
-    this.imageDao = imageDao;
-  }
+	@Autowired
+	public ImageController(ImageDao imageDao) {
+		this.imageDao = imageDao;
+	}
 
-  @RequestMapping(value = "/images/{id}", method = RequestMethod.GET, produces = MediaType.IMAGE_JPEG_VALUE)
-  public ResponseEntity<?> getImage(@PathVariable("id") long id) {
+	@RequestMapping(value = "/images/{id}", method = RequestMethod.GET, produces = MediaType.IMAGE_JPEG_VALUE)
+	public ResponseEntity<?> getImage(@PathVariable("id") long id) {
 
-    Optional<Image> image = imageDao.retrieve(id);
+		Optional<Image> image = imageDao.retrieve(id);
 
-    if (image.isPresent()) {
-      InputStream inputStream = new ByteArrayInputStream(image.get().getData());
-      return ResponseEntity.ok().contentType(MediaType.IMAGE_JPEG).body(new InputStreamResource(inputStream));
-    }
-    return new ResponseEntity<>("Image id=" + id + " not found.", HttpStatus.NOT_FOUND);
-  }
+		if (image.isPresent()) {
+			InputStream inputStream = new ByteArrayInputStream(image.get().getData());
+			return ResponseEntity.ok().contentType(MediaType.IMAGE_JPEG).body(new InputStreamResource(inputStream));
+		}
+		return new ResponseEntity<>("Image id=" + id + " not found.", HttpStatus.NOT_FOUND);
+	}
 
-  @RequestMapping(value = "/images/{id}", method = RequestMethod.DELETE)
-  public ResponseEntity<?> deleteImage(@PathVariable("id") long id) {
+	@RequestMapping(value = "/images/{id}", method = RequestMethod.DELETE)
+	public ResponseEntity<?> deleteImage(@PathVariable("id") long id) {
 
-    Optional<Image> image = imageDao.retrieve(id);
+		Optional<Image> image = imageDao.retrieve(id);
 
-    if (image.isPresent()) {
-      imageDao.delete(image.get());
-      return new ResponseEntity<>("Image id=" + id + " deleted.", HttpStatus.OK);
-    }
-    return new ResponseEntity<>("Image id=" + id + " not found.", HttpStatus.NOT_FOUND);
-  }
+		if (image.isPresent()) {
+			imageDao.delete(image.get());
+			return new ResponseEntity<>("Image id=" + id + " deleted.", HttpStatus.OK);
+		}
+		return new ResponseEntity<>("Image id=" + id + " not found.", HttpStatus.NOT_FOUND);
+	}
 
-  @RequestMapping(value = "/images", method = RequestMethod.POST)
-  public ResponseEntity<?> addImage(@RequestParam("file") MultipartFile file, RedirectAttributes redirectAttributes) {
+	@RequestMapping(value = "/images", method = RequestMethod.POST)
+	public ResponseEntity<?> addImage(@RequestParam("file") MultipartFile file, RedirectAttributes redirectAttributes) {
 
-    String contentType = file.getContentType();
-    if (!contentType.equals(MediaType.IMAGE_JPEG.toString())) {
-      return new ResponseEntity<>("Only JPEG file format supported", HttpStatus.UNSUPPORTED_MEDIA_TYPE);
-    }
+		String contentType = file.getContentType();
+		if (!contentType.equals(MediaType.IMAGE_JPEG.toString())) {
+			return new ResponseEntity<>("Only JPEG file format supported", HttpStatus.UNSUPPORTED_MEDIA_TYPE);
+		}
 
-    try {
-      imageDao.create(new Image(file.getOriginalFilename(), file.getBytes()));
-    } catch (IOException e) {
-      return new ResponseEntity<>("Failure to read file", HttpStatus.NO_CONTENT);
-    }
-    return new ResponseEntity<>("Image uploaded", HttpStatus.OK);
-  }
+		try {
+			imageDao.create(new Image(file.getOriginalFilename(), file.getBytes()));
+		} catch (IOException e) {
+			return new ResponseEntity<>("Failure to read file", HttpStatus.NO_CONTENT);
+		}
+		return new ResponseEntity<>("Image uploaded", HttpStatus.OK);
+	}
 
-  @RequestMapping(value = "/images", method = RequestMethod.GET, produces = "application/json")
-  @ResponseBody
-  public ArrayNode getImageList() {
-    List<Image> images = imageDao.retrieveAll();
-    ArrayNode nodes = mapper.createArrayNode();
-    for (Image image : images) {
-      ObjectNode objectNode = mapper.createObjectNode();
-      objectNode.put("id", image.getId());
-      objectNode.put("name", image.getName());
-      nodes.add(objectNode);
-    }
-    return nodes;
-  }
+	@RequestMapping(value = "/images", method = RequestMethod.GET, produces = "application/json")
+	@ResponseBody
+	public ArrayNode getImageList() {
+		List<Image> images = imageDao.retrieveAll();
+		ArrayNode nodes = mapper.createArrayNode();
+		for (Image image : images) {
+			ObjectNode objectNode = mapper.createObjectNode();
+			objectNode.put("id", image.getId());
+			objectNode.put("name", image.getName());
+			nodes.add(objectNode);
+		}
+		return nodes;
+	}
 
 }
diff --git a/backend/src/main/java/pdl/backend/ImageDao.java b/backend/src/main/java/pdl/backend/ImageDao.java
index 1908f44..ca1474b 100644
--- a/backend/src/main/java/pdl/backend/ImageDao.java
+++ b/backend/src/main/java/pdl/backend/ImageDao.java
@@ -15,44 +15,44 @@ import org.springframework.stereotype.Repository;
 @Repository
 public class ImageDao implements Dao<Image> {
 
-  private final Map<Long, Image> images = new HashMap<>();
+	private final Map<Long, Image> images = new HashMap<>();
 
-  public ImageDao() {
-    final ClassPathResource imgFile = new ClassPathResource("test.jpg");
-    byte[] fileContent;
-    try {
-      fileContent = Files.readAllBytes(imgFile.getFile().toPath());
-      Image img = new Image("test.jpg", fileContent);
-      images.put(img.getId(), img);
-    } catch (final IOException e) {
-      e.printStackTrace();
-    }
-  }
+	public ImageDao() {
+		final ClassPathResource imgFile = new ClassPathResource("test.jpg");
+		byte[] fileContent;
+		try {
+			fileContent = Files.readAllBytes(imgFile.getFile().toPath());
+			Image img = new Image("test.jpg", fileContent);
+			images.put(img.getId(), img);
+		} catch (final IOException e) {
+			e.printStackTrace();
+		}
+	}
 
-  @Override
-  public Optional<Image> retrieve(final long id) {
-    return Optional.ofNullable(images.get(id));
-  }
+	@Override
+	public Optional<Image> retrieve(final long id) {
+		return Optional.ofNullable(images.get(id));
+	}
 
-  @Override
-  public List<Image> retrieveAll() {
-    return new ArrayList<Image>(images.values());
-  }
+	@Override
+	public List<Image> retrieveAll() {
+		return new ArrayList<Image>(images.values());
+	}
 
-  @Override
-  public void create(final Image img) {
-    images.put(img.getId(), img);
-  }
+	@Override
+	public void create(final Image img) {
+		images.put(img.getId(), img);
+	}
 
-  @Override
-  public void update(final Image img, final String[] params) {
-    img.setName(Objects.requireNonNull(params[0], "Name cannot be null"));
+	@Override
+	public void update(final Image img, final String[] params) {
+		img.setName(Objects.requireNonNull(params[0], "Name cannot be null"));
 
-    images.put(img.getId(), img);
-  }
+		images.put(img.getId(), img);
+	}
 
-  @Override
-  public void delete(final Image img) {
-    images.remove(img.getId());
-  }
+	@Override
+	public void delete(final Image img) {
+		images.remove(img.getId());
+	}
 }
diff --git a/backend/src/test/java/pdl/backend/ImageControllerTests.java b/backend/src/test/java/pdl/backend/ImageControllerTests.java
index 568fa57..5165217 100644
--- a/backend/src/test/java/pdl/backend/ImageControllerTests.java
+++ b/backend/src/test/java/pdl/backend/ImageControllerTests.java
@@ -57,7 +57,7 @@ public class ImageControllerTests {
 	@Test
 	@Order(4)
 	public void deleteImagesShouldReturnMethodNotAllowed() throws Exception {
-	this.mockMvc.perform(delete("/images")).andDo(print()).andExpect(status().isMethodNotAllowed());
+		this.mockMvc.perform(delete("/images")).andDo(print()).andExpect(status().isMethodNotAllowed());
 	}
 
 	@Test
@@ -76,7 +76,8 @@ public class ImageControllerTests {
 	@Order(7)
 	public void createImageShouldReturnSuccess() throws Exception {
 		final ClassPathResource imgFile = new ClassPathResource("test.jpg");
-		MockMultipartFile multipartFile = new MockMultipartFile("file", "test.jpg", "image/jpeg", imgFile.getInputStream());
+		MockMultipartFile multipartFile = new MockMultipartFile("file", "test.jpg", "image/jpeg",
+				imgFile.getInputStream());
 		this.mockMvc.perform(MockMvcRequestBuilders.multipart("/images").file(multipartFile)).andDo(print())
 				.andExpect(status().isOk());
 	}