Fix buck build, include the MenuExtenderPlugin as GWT module

The buck build didn't include the MenuExtenderPlugin as a GWT module.
Because of that, loading of the UI from the plugin failed.

Change-Id: Ic8ed19ccc8ecf924c3bda3bce4c8107a869b607a
diff --git a/BUCK b/BUCK
index f6d9448..2ea01c2 100644
--- a/BUCK
+++ b/BUCK
@@ -1,7 +1,10 @@
+MODULE = 'com.googlesource.gerrit.plugins.menuextender.MenuExtenderPlugin'
+
 gerrit_plugin(
   name = 'menuextender',
   srcs = glob(['src/main/java/**/*.java']),
-  resources = glob(['src/main/resources/**/*']),
+  resources = glob(['src/main/**/*']),
+  gwt_module = MODULE,
   manifest_entries = [
     'Gerrit-PluginName: menuextender',
     'Gerrit-Module: com.googlesource.gerrit.plugins.menuextender.Module',