Adding pervasive column sorting

app/templates/admin/_roles_table.html

@@ -1,7 +1,7 @@
 <div id="role-list" class="card">
-  <table class="table">
+  <table class="table sortable">
     <thead>
-      <tr><th>ID</th><th>Name</th><th>Description</th><th>Permissions</th><th>Default</th><th></th></tr>
+      <tr><th>ID</th><th>Name</th><th>Description</th><th data-sort-off>Permissions</th><th data-sort-off>Default</th><th></th></tr>
     </thead>
     <tbody>
       {% for r in roles %}