Refactored user roles

app/views/admin/users/_user_tr.html.erb

@@ -25,7 +25,7 @@
   </td>
   <td class="p-2 py-3 text-nowrap">
     <span class="inline-flex -space-x-px overflow-hidden rounded-md bg-white shadow divide-x divide-gray-300">
-      <% User::AVAILABLE_ROLES.each do |role| %>
+      <% User.roles.keys.each do |role| %>
         <% if allowed_to? :change_role?, user  %>
           <% if user.role == role.to_s %>
             <%= button_to role, admin_user_path(user), method: :patch, params: { user: { role: role }}, form_class: "inline", class: "inline-block px-4 py-2 text-sm uppercase font-medium focus:relative bg-role-#{role}-light text-#{role}" %>