title: Umbrella application error when trying to create a migration with ecto elixir
body: <p>I'm trying to create a migration using the command <code>mix ecto.gen.migration &lt;migration_name&gt;</code> and I'm getting the error:</p>
  
  <pre><code>Cannot run task "ecto.gen.migration" from umbrella application
  </code></pre>
  
  <p>Why I'm getting this error?</p>