Added DB schema for custom-metrics credentials management (#373)
Added DB schema for custom-metrics credentials management (#373)

* Added DB schema for custom-metrics credentials management

* Deleted binding_id column

* Update api.db.changelog.yml

qibobo/app-autoscaler,qibobo/app-autoscaler,cloudfoundry-incubator/app-autoscaler,cloudfoundry-incubator/app-autoscaler,cloudfoundry-incubator/app-autoscaler,cloudfoundry-incubator/app-autoscaler,qibobo/app-autoscaler,qibobo/app-autoscaler