Postgres backend support

[theromis]

No description provided.

[thoas]

Having a PostgreSQL backend is a good idea but I can’t accept this PR since it relies on not needed dependencies, in this case an ORM is clearly not needed and we should only use standard library which contains everything you need.

The good side is this PR is great and a good idea!

[theromis]

ok, will try to change it to basic "native" go postgres stuff
I believe we talking about https://github.com/lib/pq may be will send something tonight

[theromis]

@thoas Started changes for github.com/lib/pq and realized this library doesn't implement reconnect, pooling and a lot of other "tasty" stuff, all this situations we have to implement manually in the code here, seems like switching will just add more problems. What do you think?

[theromis]

@thoas What do you think about merging this PR?

[thoas]

it needs to be refactored first with this architecture to avoid embed an unnecessary dependency (go-pg/pg).

[theromis]

@thoas what do you want to see there instead of go-pg/pg?

[thoas]

@theromis I don't want anything instead of go-pg/pg, we just need to isolate backends to avoid unnecessary dependency. For example, if I only use the redis backend I don't want the others dependencies.

[theromis]

@thoas https://github.com/lib/pq is this one fine?
If so https://github.com/go-pg/pg same extra library as lib/pq if we not using go-pg/pg/orm it not adding this dependency, and in this case they equal (only one reqest uses it, can replace by actual SQL query). If check https://github.com/go-pg/pg/blob/master/go.mod there is no dependency to this lib/pq, go-pg implements row pg protocol so they are equal, just can't see any benefits of replacing one by another.

[theromis]

@thoas will go-pg/orm removal work for you or you prefer to replace go-pg by lib/pq completely?