title: UserManager.GetRoles doesn't work after extending the IdentityUserRole in MVC 5 Dot Net Identity
body: <p>I have extended the IdentityUserRole by adding a foreign key column and now I am unable to Authorize or retrieve Roles information. Could please anyone help me in sorting out this issue. </p>
  
  <p>My IdentityUserRole has a foreign key column from AspNetApplications table and the IdentityUserRole extension is as follow</p>
  
  <pre><code>public class AspNetUserRoles : IdentityUserRole
  {
      [Key]
      public string ApplicationId { get; set; }
  
      [ForeignKey("ApplicationId")]
      public AspNetApplications AspNetApplications { get; set; }
  }
  </code></pre>
  
  <p>After adding the migration I can see the foreign key column is created in AspNetUserRoles table. A screen shot of the table is as follow </p>
  
  <p><a href="https://i.stack.imgur.com/Fxxdj.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Fxxdj.png" alt="enter image description here"></a></p>
  
  <p>Here I have two questions to ask</p>
  
  <ol>
  <li>Why it has created an auto Discriminator column and how I can remove it, if it has any overhead.</li>
  <li>What extra I have to do in order to get my Authorization and UserManager.GetRoles working as they were before doing this extension.</li>
  </ol>