title: Change default IDE in Unity
body: <p>How to tell Unity 3d to open Scripts with Monodevelop?</p>
  
  <p>My system run's :</p>
  
  <ul>
  <li>Ubuntu 17.10 </li>
  <li>MonoDevelop 5.10</li>
  <li>Unity 2017.3.0p2</li>
  </ul>
  
  <p>Usualy, under windows, Unity will open scripts with Visual Studio when double clicked.</p>
  
  <p>I am under linux and to achieve the same thing I have to use Monodevelop.
  Everything is working fine but I would like unity to launch Monodevelop to edit the scripts.</p>
  
  <p>Most forum are saying that unity should launch mono to edit script but for some reason my built is not. If I try to open a script within Unity there is just nothing hapening. Its not even asking me how should it open the file.</p>
  
  <p>Anyone know how to do this?</p>