fix: custom method for adding grid action

since for now, we are using custom grid action class

tailbone/grids/core.py

@@ -1544,6 +1544,11 @@ class Grid(WuttaGrid):
         self._table_data = results
         return self._table_data
 
+    # TODO: remove this when we use upstream GridAction
+    def add_action(self, key, **kwargs):
+        """ """
+        self.actions.append(GridAction(self.request, key, **kwargs))
+
     def set_action_urls(self, row, rowobj, i):
         """
         Pre-generate all action URLs for the given data row.  Meant for use