title: Error installing rubyMine, no SDK specified, but it is listed
body: <p>Getting "Could not install gems:no SDK specified" when trying to run any command such as starting the rails server.  Why am I getting this and how can I get around it?<br>
  I've had issues before with the JDK but not seen this SDK error.</p>
  
  <p><img src="https://i.stack.imgur.com/jCOF8.png" alt="enter image description here"></p>