title: Meteor role do not exist inside a method but in another
body: <p>I'm using the alanning role package in a meteor application.
  I created an admin role and I'm setting this role in another method whithout problem.</p>
  
  <p>But in a method I use : <code>Roles.setUserRoles( userID, 'admin', groupID );</code>.
  I get a Error: <code>Role 'admin' does not exist</code>. but I know admin exists and I am using the same line in an other methods.</p>
  
  <p>So my question is: What could lead to this error ? (a role do not exist in a method but in another)</p>
  
  <p>Thanks!</p>