title: ActiveRecord changes my binary column to a string column, for some reason, on migration
body: <p>Using Ruby on Rails 3 and ActiveRecord 3.2.18. I have a binary column in my database. It holds binary stuff, and actually I have a bunch of records in production with that column filled. So in my <code>db/schema.rb</code> file I had...</p>
  
  <pre><code>...
  t.binary   "tin"
  ...
  </code></pre>
  
  <p>Now, after running a migration that touches this table but doesn't change that column, my schema says...</p>
  
  <pre><code>...
  t.string "tin"
  ...
  </code></pre>
  
  <p>Well... I know that a string might be binary, and binary might be a string, depending on how it's stored in the database, and maybe these equate to the same column type in the end, but why is this happening and what can I do to fix it? Is it safe to deploy this change to production or will it hose my binary columns?</p>