title: Setting a field to read-only in Rails after it's created
body: <p>I'd like to protect a user-generated entry in a field after its initial creation.</p>
  
  <p>I'm asking the user for a unique name when they set up a project, and I want to stop that being changeable after the creation.</p>
  
  <p>Is there a way to do this in Rails? Can I set it as attr_accessible at first then switch it to to attr_protected?</p>
  
  <p>Cheers</p>