title: Why am I suddenly getting Missing Template errors with edge Rails (2.3)?
body: <p>After freezing edge rails, all my controller examples are failing with
  MissingTemplate errors.
  e.g., "Missing template attachments/create.erb in view path app/views"</p>
  
  <p>Trying to actually render the views gives me the same error.</p>
  
  <p>I noticed I can fix most of them by using respond_to but I usually
  never use it. I almost always only need to respond to one format in
  one action so I omit respond_to and let Rails figure out which file to
  render.</p>
  
  <p>Does Rails suddenly require respond_to blocks in every action as of 2.3?</p>