title: Rolify has_role? method returning false instead of true
body: <p>I have added Rolify gem to my project and successfully initialised it. I am facing a strange problem?</p>
  
  <p>The user object has user and admin roles.</p>
  
  <pre><code>[1] pry(#&lt;API::V1::PostPolicy&gt;)&gt; current_user.roles
  =&gt; [#&lt;API::V1::Role:0x007fb70602be48
    id: "19810121-ea16-4d86-b36c-475fad0f7dec",
    name: "user",
    resource_id: nil,
    resource_type: nil,
    created_at: Thu, 02 Apr 2015 02:05:27 UTC +00:00,
    updated_at: Thu, 02 Apr 2015 02:05:27 UTC +00:00&gt;,
   #&lt;API::V1::Role:0x007fb705ee6858
    id: "a51c59e2-9dd0-4838-b159-1af11f7db15d",
    name: "admin",
    resource_id: nil,
    resource_type: nil,
    created_at: Thu, 02 Apr 2015 02:05:27 UTC +00:00,
    updated_at: Thu, 02 Apr 2015 02:05:27 UTC +00:00&gt;]
  </code></pre>
  
  <p>When I query for admin roles, I see a strange behavior.</p>
  
  <pre><code>[2] pry(#&lt;API::V1::PostPolicy&gt;)&gt; current_user.has_role? :admin
  =&gt; false
  </code></pre>
  
  <p>I am trying to enforce policies using Pundit and Rolify and the above output is from Policy test.</p>
  
  <p>V</p>
  
  <p><strong>Update</strong></p>
  
  <p>I am using UUID with rolify. The migration for rolify is as follows.</p>
  
  <pre><code>   class RolifyCreateAPIV1Roles &lt; ActiveRecord::Migration
        def change
          create_table :api_v1_roles, id: :uuid do |t|
            t.string :name
            t.uuid :resource_id
            t.string :resource_type
  
            t.timestamps
         end
  
      create_table(:api_v1_users_api_v1_roles, :id =&gt; false) do |t|
        t.uuid :user_id
        t.uuid :role_id
      end
  
      add_index(:api_v1_roles, :name)
      add_index(:api_v1_roles, [ :name, :resource_type, :resource_id ])
      add_index(:api_v1_users_api_v1_roles, [ :user_id, :role_id ])
    end
  end
  </code></pre>