Fix checkstyle errors

src/Common/src/main/java/greenify/common/UserDTO.java

@@ -4,15 +4,15 @@ package greenify.common;
 // is an object that carries data between processes.
 // The motivation for its use is that communication between processes is usually done
 // resorting to remote interfaces (e.g., web services), where each call is an expensive operation.
-public class UserDTO {
+public class UserDto {
 
     private Long id;
     private String name;
 
-    public UserDTO() {
+    public UserDto() {
     }
 
-    public UserDTO(Long id, String name) {
+    public UserDto(Long id, String name) {
         this.id = id;
         this.name = name;
     }

src/Common/src/test/java/UserDTOTest.java

@@ -1,14 +1,14 @@
-import greenify.common.UserDTO;
+import greenify.common.UserDto;
 import org.junit.Test;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
-public class UserDTOTest {
+public class UserDtoTest {
     @Test
     public void setAndGetTest() {
-        UserDTO user = new UserDTO(1L, "greenify");
-        UserDTO testUser = new UserDTO();
+        UserDto user = new UserDto(1L, "greenify");
+        UserDto testUser = new UserDto();
         testUser.setId(1L);
         testUser.setName("greenify");
         assertTrue(user.getId() == 1L);
@@ -17,8 +17,8 @@ public class UserDTOTest {
 
     @Test
     public void equalsTest() {
-        UserDTO first = new UserDTO(1L, "greenify");
-        UserDTO second = new UserDTO(1L, "greenify");
+        UserDto first = new UserDto(1L, "greenify");
+        UserDto second = new UserDto(1L, "greenify");
         assertEquals(first.getId(), second.getId());
         assertEquals(first.getName(), second.getName());
     }