title: How to use two gruntfiles for the same project/folder?
body: <p>i think i am in a special situation.</p>
  
  <p>I am building a website and a mobile web-app based on the same source (with a few expectation like e.g. the index.html)</p>
  
  <p>But that's why I need need two Gruntfiles to configure the build-tasks for each project separately (the site and the app).</p>
  
  <p><strong>How can I work with two gruntfiles?</strong> </p>
  
  <p>PS: I tried to work with "grunt targets" but plugins like e.g. useminPrepare do not support targets yet.</p>