title: rake db:migrate securely on staging and production environments
body: <p>I enjoy using rake to manage my migrations in the development environment, where I have allowed my rails app full permissions on the dev DB. </p>
  
  <p>However, in the staging and production environments, my application only has write access, not  the ability to alter tables.</p>
  
  <p>I'd like to continue using <code>rake db:migrate</code> in staging and production, but the problem is that <code>rake db</code> uses the same user as my rails app, which doesn't have sufficient privileges.</p>
  
  <p>Does anyone know an easy way around this problem, without having to allow administrative db privileges in my rails app.</p>
  
  <p>Eg, if I could specify <code>-username</code> and <code>-password</code> when I run <code>rake db</code>, that would be great.</p>