micro-compose: launch greeter-srv and expose port to host network

docker-compose.yml

# Source: https://github.com/mcoquet/micro-compose
# 
# run docker-compose with: 
# > EXTERNAL_IP="192.168.1.65" GREETER_SRV_PORT="1234" docker-compose up
# 
# Query micro greeter service from host
# > micro query go.micro.srv.greeter Say.Hello '{"name": "John"}'
#
# Query micro greeter service from host (launch container to run micro cli tool - usefull if you do not have gomicro tools installed)
# > docker run --net=host microhq/micro --registry_address=localhost:8500 query go.micro.srv.greeter Say.Hello '{"name": "John"}'

version: "2"
services:
  consul:
    command: agent -dev -client 0.0.0.0
    image: consul:latest
    ports:
    - "8300:8300"
    - "8400:8400"
    - "8500:8500"
    - "8600:53/udp"
  api:
    command: --registry_address=consul:8500 --enable_stats --register_interval=5 --register_ttl=10 api
    image: microhq/micro:latest
    depends_on:
    - consul
    ports:
    - "8080:8080"
  sidecar:
    command: --registry_address=consul:8500 --register_interval=5 --register_ttl=10 sidecar
    image: microhq/micro:latest
    depends_on:
    - consul
    ports:
    - "8081:8081"
  web:
    command: --registry_address=consul:8500 --register_interval=5 --register_ttl=10 web
    image: microhq/micro:latest
    depends_on:
    - consul
    ports:
    - "8082:8082"
  greeter:
    command: --registry_address=consul:8500 --server_address=:${GREETER_SRV_PORT} --server_advertise=${EXTERNAL_IP}:${GREETER_SRV_PORT} greeter-srv
    image: microhq/greeter-srv:latest
    depends_on:
    - consul
    ports:
    - "${GREETER_SRV_PORT}:${GREETER_SRV_PORT}"