title: Unable to track an entity of type because primary key property 'id' is null
body: <p>After I upgraded to Asp.Net Core 3.0 I am getting the following error for my Identity class when attempting to create a user:</p>
  
  <blockquote>
    <p>Unable to track an entity 'User' of type because primary key property
    'id' is null.</p>
  </blockquote>
  
  <p>Here User represents my extension of the Identity model.</p>
  
  <p>This is the line of code where the error occurs:</p>
  
  <pre><code>var result = await _userManager.CreateAsync(user, password);
  </code></pre>