Implements function for Username Update

src/main/java/CredentialRepository.java

@@ -74,6 +74,13 @@ public class CredentialRepository implements CredentialRepositoryInterface{
 
     public void updateUsername(int index, String newUsername){
 
+        try{
+            this.credentials.get(index).updateUsername(newUsername);
+        }
+        catch (IndexOutOfBoundsException outOfBoundsException)
+        {
+
+        }
     }
 
     @Override

src/test/java/CredentialRepositoryTest.java

@@ -69,7 +69,7 @@ class CredentialRepositoryTest {
 
         Credential c = this.credentialRepository.getCredentialsViaId(0);
 
-        Assertions.assertEquals("newPassword", c.getName());
+        Assertions.assertEquals("newUsername", c.getName());
 
     }