improve plugin structure

plugins/scm-hg-plugin/src/main/java/sonia/scm/api/rest/resources/HgConfigResource.java

@@ -47,13 +47,13 @@ public class HgConfigResource
    * Constructs ...
    *
    *
-   * @param repositoryManager
+   *
+   * @param handler
    */
   @Inject
-  public HgConfigResource(RepositoryManager repositoryManager)
+  public HgConfigResource(HgRepositoryHandler handler)
   {
-    handler = (HgRepositoryHandler) repositoryManager.getHandler(
-      HgRepositoryHandler.TYPE_NAME);
+    this.handler = handler;
   }
 
   //~--- get methods ----------------------------------------------------------

plugins/scm-hg-plugin/src/main/java/sonia/scm/repository/HgRepositoryHandler.java

@@ -9,6 +9,8 @@ package sonia.scm.repository;
 
 //~--- non-JDK imports --------------------------------------------------------
 
+import com.google.inject.Singleton;
+
 import sonia.scm.ConfigurationException;
 import sonia.scm.io.CommandResult;
 import sonia.scm.io.ExtendedCommand;
@@ -37,6 +39,7 @@ import java.util.logging.Logger;
  *
  * @author Sebastian Sdorra
  */
+@Singleton
 public class HgRepositoryHandler extends AbstractRepositoryHandler<HgConfig>
 {