Override omero.db.name (fix #16)

[joshmoore]

omego assumes that the DBHOSE and DBNAME are set via
bin/omero config. DBNAME was previously not set to
prevent an accidental upgrade of a database. Here we
set DBNAME only if the database has not been created
elsewhere.

[joshmoore]

version: '3'

# Minimal docker compose file

services:
  db:
    image: postgres
    environment:
      - POSTGRES_USER=omero
      - POSTGRES_PASSWORD=omero
  omero:
    build: .
    environment:
      - ROOTPASS=omero
      - CONFIG_omero_upgrades_url=
      - CONFIG_Ice_IPv6=0

[joshmoore]

There's a bug here in that the bin/omero config setting is overwritten on restart. This will need to be turned into a file in the config/ directory minimally. @manics : it would still be worthwhile to have your opinion on the logic, i.e. setting this value only on init rather than upgrade.

[manics]

I think the init vs upgrade logic in this PR is too complicated, and we'd be better off giving them the same behaviour. If you want to make a breaking change to omego I'm fine with that.

[joshmoore]

@manics : you were right, this will require omego work.

[joshmoore]

@manics, and one more? ;)