Add support for multiple services

[kalyanramu]

in app.yaml in github, add
servicename : zoryascheduler

This will not override any default services and create a new service/app. This should be a simple update.

[eranchetz]

@kalyanramu I agree it's best to deploy application as a different service (and not default)
however, if some has already deployed Zorya and will deploy with the new service name he will have 2 instances running.

I think it's better to document this and let people choose a service name manually.

WDYT?