'Establish the connection with the mongo backend and connect to the collections
:param collection: ignores but provided for consistency w/ other doc_store_config patterns'

def __init__(self, host, db, port=27017, tz_aware=True, user=None, password=None, bucket='fs', collection=None, **kwargs):

    proxy = False
    mongo_db = connect_to_mongodb(db, host, port=port, tz_aware=tz_aware, user=user, password=password, proxy=proxy, **kwargs)
    self.fs = gridfs.GridFS(mongo_db, bucket)
    self.fs_files = mongo_db[(bucket + '.files')]
    self.chunks = mongo_db[(bucket + '.chunks')]
