[20160719172302] Health Check and Instance Autoscaling Configuration

Much thanks to @beedub for two great PRs adding some powerful configuration options to Convox!

Health Check Configuration

You can now configure the health checks for your Convox apps using additional labels in your docker-compose.yml (#772)

labels:
  - convox.health.port=443
  - convox.health.path=/ping
  - convox.health.timeout=30
ports:
  - 443:5000

Autoscaling Parameters

You can now set the InstanceUpdateBatchSize to configure the rate at which new instances are rolled into your Convox Rack during updates.

convox rack params set InstanceUpdateBatchSize=3