GroupsResource for sandbox
Merge branch 'develop' into feature/issue-644-groups-resource
add get_by_name() get_or_create_by_name(), remove get_by_key()
docstrings
Merge branch 'feature/issue-644-groups-resource' into develop
Merge branch 'develop' of github.com:praekelt/vumi-go into develop
removing unused import (thanks @jerith)
Merge branch 'develop' into feature/issue-639-old-conversation-cleanup-pt-1