title: web.config - auto generate a release version
body: <p>Simple task, but for some reason no simple solution just yet.</p>
  
  <p>We've all got web.config files - and I haven't worked anywhere yet that doesn't have the problem where someone yells across the room "Sh*t, I've just uploaded the wrong web.config file".</p>
  
  <p>Is there a simple way of being able to auto generate a web.config file that will contain the right things for copying to release?  An example of these being:</p>
  
  <ul>
  <li>Swap connection string over to use live database</li>
  <li>Change 
  <li>Switch over to use the live/release logging system, and live/release security settings</li>
  <li>(in our case we need to change the SessionState mode to InProc from StateServer - this isn't normal)</li>
  </ul>
  
  <p><em>If you have others, let me know and I'll update it here so it's easy for someone else to find</em></p>
  
  <p>Maintaining 2 config files works, but is a royal pain, and is usually the reason something's gone wrong while you're pushing things live.</p>