Competition retrieval

- Added competition relationship to Article.
- ArticleRepository now returns competition object as part of
Promotions type articles
- New models to support competitions and questions
- ArticleTransformer now looks for competition
- New CompetitionTransformer
- Updated routes for promotions. They now come under the user endpoint
- Updates tests for promotions to reflect new routing
Merge branch 'promotions' into dev

Conflicts:
	web/app/Apiv1/Transformers/ArticleTransformer.php