title: How to copy data from SQLite3 to MySQL?
body: <p>I have an older Rails 3 app that use SQLite3 database. I need to switch it to MySQL - that's kind of easy-peasy.</p>
  
  <p>The problem is that in the SQLite3 database is a scheme of categories - about 500. I need to export these categories from SQLite3 database and import them into the newly create MySQL one.</p>
  
  <p>Now the thing is (as I haven't done it before) - how to make this kind of migration in its simplest way?</p>