mysql race condition (specifically when containerized)

[JakeDEvans]

When using containers, and building mysql + ara, it may take time to have mysql ready for connection, ara does not wait for this and fails in the boot process.

ara_1 | sqlalchemy.exc.OperationalError: (pymysql.err.OperationalError) (2003, "Can't connect to MySQL server on 'mysql' ([Errno 113] No route to host)")`

If possible, please add a try/catch/retry operation.