title: create migration for model that in subdirectory
body: <p>I have a 'question' model in Subdirectory Exceed::Question.</p>
  
  <p>now I want to add migration for Question model, so I run</p>
  
  <p><code>rails g migration AddImageToExceedQuestions</code></p>
  
  <p>after that when I run `rake db:migrate</p>
  
  <p>Its show error -</p>
  
  <pre><code>Mysql2::Error: Table 'bs_development.questions' doesn't exist: ALTER TABLE `questions`
  </code></pre>
  
  <p>In my database question model save as <strong>exceed_question</strong>.</p>
  
  <p>I also try <code>rails g migration AddImageToQuestions</code> and <code>rails g migration AddImageToExceed::Questions</code> but get same error.</p>
  
  <p>How I can create migration for model that in subdirectory.</p>