Allow passing arbitrary attrs when rendering grid

tailbone/grids/core.py

@@ -375,6 +375,7 @@ class Grid(object):
         elif self.width == 'half':
             grid_class = 'half'
         context['grid_class'] = '{} {}'.format(grid_class, context.get('grid_class', ''))
+        context.setdefault('grid_attrs', {})
         return render(template, context)
 
     def get_default_filters(self):

tailbone/templates/grids/grid.mako

@@ -1,5 +1,5 @@
 ## -*- coding: utf-8; -*-
-<div class="grid ${grid_class}">
+<div class="grid ${grid_class}" ${h.HTML.render_attrs(grid_attrs)}>
   <table>
     ${grid.make_webhelpers_grid()}
   </table>