inject `TARGET_ONE_HOST` in `app_a` for customization

[larrycai]

services:
  app-a:
    build: .
    ports:
      - "8000:8000"
    volumes:
      - ./src/fastapi_jaeger:/app
    environment:
      TARGET_ONE_HOST: "fastapi-jaeger_app-b_1"
      TARGET_TWO_HOST: "fastapi-jaeger_app-c_1"

In the docker-composer.yaml, it is better to inject above configurations (TARGET_ONE_HOST & TARGET_TWO_HOST

related with #2 (app_b could be good enough)

[blueswen]

Great advice! Add TARGET_ONE_HOST and TARGET_TWO_HOST env var to compose file in the latest commit.

[larrycai]

Thanks