PostgreSQL cleanup / documentation

[znmeb]

Approximately prioritized - feel free to adjust:

• [x] 1. Establish ground truth source for database dumps
• [x] 2. Make sure all images have latest PostgreSQL client packages (10.1); add them if needed.
• [x] 3. Add "wait for PostgreSQL" scripts to all images that connect to PostGIS
• [ ] 4. Document PostgreSQL image startup processes and environment variables
• [ ] 5. Merge crash data ingestion into https://github.com/hackoregon/transportation-system-backend
• [ ] 6. Merge ridership data ingestion into https://github.com/hackoregon/transportation-system-backend
• [ ] 7. Merge PostGIS image construction into https://github.com/hackoregon/transportation-system-backend, including building with Travis CI as is done with the GeoDjango image.

Dependency - needs to wait for the ODOT crash dump API to be merged to master. Some of this will be done in branches to https://github.com/hackoregon/transportation-system-backend.

[znmeb]

Most of this is done "Ground truth" for TriMet ridership and ODOT crash data is in Google Drive "Compressed Dumps" folder. Congestion will be up there early 2018-02-21. I'm holding off on consolidating repositories until I know I don't need to fix any data issues with the ridership data.

Given its size, I think the congestion dataset isn't going to get lumped in with the other twol

[znmeb]

Closing - we have all this done