corrected boolean check

src/main/java/de/hftstuttgart/utils/GitTeaUtil.java

@@ -74,7 +74,7 @@ public class GitTeaUtil {
         } catch (ApiException e) {
             LOG.error("Error while deleting repository:" + e.getMessage());
         }
-        return repository == null;
+        return repository != null;
     }
 
     private void setupAuth() {