Use In-Memory PostgreSQL Instance for Testing

[DanielJDufour]

In theory, it might be possible to remove the requirement to run Docker and PostgreSQL for tests, if you use an in-memory PostgreSQL instance pg-mem. The pros would be that it would be easier for developers to get things running and less memory overhead. The cons would be that I don't think it currently supports PostGIS (are we using PostGIS functionality?) and it's not exactly the same as running PostgreSQL/PostGIS.

[DanielJDufour]

update: pg-mem also supports typeorm which is what aqualink api uses: https://github.com/oguimbal/pg-mem/wiki/Libraries-adapters#-typeorm