title: How to migrate a boolean field in MySQL to PostgreSQL in Heroku?
body: <p>I have a application, running with MySQL in my local machine. There is a field I define as boolean in Rails, which is represent in 0 or 1 in MySQL.</p>
  
  <p>I am now trying migrate to Heroku, which is using PostgreSQL. After push the code and database to Heroku, the app cannot run.</p>
  
  <p>There is an error message.</p>
  
  <pre><code>ActiveRecord::StatementInvalid (PGError: ERROR:  operator does not exist: boolean = integer
  </code></pre>
  
  <p>How can I fix it?</p>
  
  <p>Thanks all.</p>