title: (UndefinedFunctionError) undefined function change/2 in Model
body: <p>I run some code with <code>iex -S mix</code> </p>
  
  <p>This is ok:</p>
  
  <pre><code>user = Repo.get User, 1
  
  Ecto.Changeset.change user, %{name: "xxxx"}
  </code></pre>
  
  <p>but this is wrong:</p>
  
  <pre><code>User.change user, %{name: "xxxx"}
  </code></pre>
  
  <p>raise <code>(UndefinedFunctionError) undefined function Rumbl.User.change/2</code></p>
  
  <p>I notice there is <code>import Ecto.Changeset</code> in function model in file web.ex</p>
  
  <pre><code>def model do
    quote do
      use Ecto.Schema
  
      import Ecto
      import Ecto.Changeset
      import Ecto.Query, only: [from: 1, from: 2]
    end
  end
  </code></pre>
  
  <p>So I think User.change/2 should works as same as Ecto.Changeset.change/2, is it right?</p>