title: Migration: No DbContext was found in assembly
body: <p>Using VS Community 2017. I have tried to create initial migration with error message saying: </p>
  
  <blockquote>
    <p>Both Entity Framework Core and Entity Framework 6 are installed. The Entity Framework Core tools are running. Use 'EntityFramework\Add-Migration' for Entity Framework 6.
    No DbContext was found in assembly 'Test_Project'. Ensure that you're using the correct assembly and that the type is neither abstract nor generic.</p>
  </blockquote>
  
  <p>... code in my dbcontext:</p>
  
  <pre><code>protected override void OnModelCreating(DbModelBuilder mb)
  {
      base.OnModelCreating(mb);
  
      mb.Entity&lt;Stuff&gt;().ToTable("Stuff");
  
  }
  
  public DbSet&lt;Stuff&gt; Stuff{ get; set; }
  </code></pre>