restrict action to code-from-ds.json

src/com/rthoni/intellij/codefromds/ui/actions/GenerateAction.java

         }
         else {
             final VirtualFile file = CommonDataKeys.VIRTUAL_FILE.getData(e.getDataContext());
-            e.getPresentation().setVisible(file != null && file.getName().endsWith(".json"));
+            e.getPresentation().setVisible(file != null && file.getName().equals("code-from-ds.json"));
         }
     }
 }