title: Unable to resolve service for type in ApplicationDbContext
body: <p>When I'm trying to add migrations with <code>dnx ef migrations add Mig</code>, I have the following exception in console:</p>
  
  <blockquote>
    <p>Unable to resolve service for type
    'Microsoft.AspNet.Http.IHttpContextAcccessor' while attempting to
    activate 'NewLibrary.Models.ApplicationDbContext'.</p>
  </blockquote>
  
  <p>My <em>ApplicationDbContext</em>:</p>
  
  <pre><code>public class ApplicationDbContext : DbContext
  {
      private readonly IHttpContextAccessor _accessor;
  
      public ApplicationDbContext(IHttpContextAccessor accessor)
      {
          _accessor = accessor;
      }
  }
  </code></pre>
  
  <p>What's the problem? </p>
  
  <p>How should I correctly add dependencies to <code>ApplicationDbContext</code> constructor?</p>