Update 2014-04-02-using-modules.md
Merge pull request #1005 from kavitshah8/patch-6

Update 2014-04-02-using-modules.md
=BG= add note on cyclic dependencies unsupported

see https://github.com/stefanpenner/ember-cli/issues/1009
Merge pull request #1010 from bguiz/patch-4

add note on cyclic dependencies unsupported
Update 2014-04-02-using-modules.md
Indicate that you must import Ember and DS on website.
Merge pull request #1016 from rjackson/remove-global-reference

Indicate that you must import Ember and DS on website.