Add gem badge to readme file.
Add gem badge to readme file.

CoastDigitalGroup/cdg-subengine-devise,CoastDigitalGroup/cdg-subengine,CoastDigitalGroup/cdg-subengine-devise,CoastDigitalGroup/cdg-subengine,CoastDigitalGroup/cdg-subengine,CoastDigitalGroup/cdg-subengine-devise,PHCNetworks/multi-tenancy-devise,PHCNetworks/multi-tenancy-devise,PHCNetworks/multi-tenancy-devise