channels: added test for get_thumb.
channels: added test for get_thumb.
Merge branch 'channels_get_thumb_tests' of github.com:andrewsmedina/opps into channels_get_thumb_tests

Conflicts:
	opps/channels/tests/test_models.py
Merge pull request #151 from andrewsmedina/channels_get_thumb_tests

test for channels get_thumb