Reverts some mistakes

Implements and tests function to delete entries

@TODO: catch index left-shift after deleting an item

src/main/java/CredentialRepository.java

@@ -49,7 +49,6 @@ public class CredentialRepository implements CredentialRepositoryInterface{
            return null;
         }
 
-
     }
 
     /*
@@ -90,7 +89,23 @@ public class CredentialRepository implements CredentialRepositoryInterface{
 
     }
 
+/*
+    this function will be required in the future for catching the left-shift in the arrayList
+    after one entry was deleted. welp, maybe it won't. can't tell and i've no time atm to
+    finish this
+
 
+    private int mapIndexToListCounter(int needle) {
+        for(int c = 0; c<this.credentials.size(); c++)
+        {
+            if(this.credentials.get(c).getId() == needle)
+            {
+                return c;
+            }
+        }
+        return -1;
+    }
+*/
     private int getListSize()
     {
         return this.credentials.size();

src/test/java/CredentialRepositoryTest.java

@@ -81,9 +81,4 @@ class CredentialRepositoryTest {
         Assertions.assertEquals(null, this.credentialRepository.getCredentialsViaId(0));
     }
 
-    @Test
-    void testIndexShiftAfterDeletion(){
-
-    }
-
 }