Remove brackets from GROUP BY in rake task.
Remove brackets from GROUP BY in rake task.

For PostgreSQL 9.4.

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Coursemology/coursemology2,Coursemology/coursemology2,cysjonathan/coursemology2,Coursemology/coursemology2,Coursemology/coursemology2,cysjonathan/coursemology2,Coursemology/coursemology2,Coursemology/coursemology2,Coursemology/coursemology2,cysjonathan/coursemology2