added getId to ModelObject interface

scm-core/src/main/java/sonia/scm/ModelObject.java

@@ -43,4 +43,14 @@ import java.io.Serializable;
  */
 public interface ModelObject
         extends TypedObject, LastModifiedAware, Cloneable, Validateable,
-                Serializable {}
+                Serializable
+{
+
+  /**
+   * Method description
+   *
+   *
+   * @return
+   */
+  public String getId();
+}

scm-core/src/main/java/sonia/scm/group/Group.java

@@ -363,6 +363,18 @@ public class Group implements ModelObject, Iterable<String>
     return description;
   }
 
+  /**
+   * Method description
+   *
+   *
+   * @return
+   */
+  @Override
+  public String getId()
+  {
+    return name;
+  }
+
   /**
    * Method description
    *

scm-core/src/main/java/sonia/scm/user/User.java

@@ -328,6 +328,18 @@ public class User implements Principal, ModelObject
     return displayName;
   }
 
+  /**
+   * Method description
+   *
+   *
+   * @return
+   */
+  @Override
+  public String getId()
+  {
+    return name;
+  }
+
   /**
    * Method description
    *