coke concurrent promises

gistfile1.js

find_all_user_emails : function ( count, next ){
  var i = Math.ceil( count / 10000 );
  var skip = 0;
  var promises = [];

  for( ; i-- ; ){
    promises.push( User.
      find({ is_verified : true })
      lean().
      select( 'email' ).
      limit( 10000 ).
      skip( skip ).
      execQ());
    skip += 10000;
  }

  Q.all( promises ).
    then( function ( many_users ){
      return Array.prototype.concat([], many_users );
    }).
    nodeify( next );
}