Minyangu docker-compose.yml

[minyangu]

• Replaced links with networks. Links is a legacy feature that should avoid using. Added networks for db and search.
• Updated default restart policy to unless-stopped.
• Added a sample .env hidden file which contains default environment variables.
• Added pgadmin for a postgres GUI. Added persistence volume for pgadmin since it needs to store its own credentials and servers.

[robotdan]

Thanks @minyangu I appreciate the PR.

It looks really good, I'll do a bit of testing on my end and then I should be able to merge in your PR. Thanks for taking the time to contribute!

[robotdan]

@minyangu I think for our default compose configuration, I'll leave out the pgadmin image. I can merge your changes in manually, or if you want to update your PR with a separate part docker-compose-pgadmin.yml that includes pgadmin and remove it from the primary docker-compose.yml I could accept it that way.

Do you have a preference?

[robotdan]

Manually merged in some of these changes to master. Thanks!