TODO: this isn't used anyhere.

AppAssignment provides the location and resource limits for an app to run.

AppDefintiion contains all the configuration needed to run a container in the galaxy environment.

TODO: logging! TODO: use CAS operations so that we don't have any races between configuration changes The consul tree looks like: galaxy/apps/env/app_name galaxy/pools/env/pool_name galaxy/hosts/env/pool/host_ip galaxy/services/env/pool/host_ip/service_name/container_id The Methods for ConsulBackend are tentatively defined here to satisfy the confing.Backend interface, and may not be appropriate */.

Interface to wrap AppConfig, so that it can be swapped out with a different Backend.