Please contact the server administrator, and inform them of the time the error occurred, and anything you might have done that may have caused the error.
MongoDB::SelectionError: No readable server available for matching read preference primary. MongoDB server status:
Topology type: Single; Member status:
localhost:27017 (type: Unknown, error: MongoDB::NetworkError: Could not connect to 'localhost:27017': IO::Socket::INET: connect: Connection refused )