implement PostgreSQL sessions

[giuppep]

Integrating flask-pg-session into flask-session.

To do:

• [x] tests
• [x] documentation

[Lxstr]

What are you thoughts on using SESSION_POSTGRESQL = ThreadedConnectionPool(...) rather that using SESSION_POSTGRESQL_MAX_DB_CONN and uri? This would be more similar to most of the other backends (SQLALchemy is a bit different)?

[giuppep]

What are you thoughts on using SESSION_POSTGRESQL = ThreadedConnectionPool(...) rather that using SESSION_POSTGRESQL_MAX_DB_CONN and uri? This would be more similar to most of the other backends (SQLALchemy is a bit different)?

Yeah, makes sense, will implement it like this. I just don't think it should be optional as there is no way to guess the URI of the database (even if we assume the db is on localhost, you still need to specify the db name).

[Lxstr]

Awesome! For some reason the multiple python version test strategy isn't working, because some of those optional parameter type hints should fail for 3.8. Everything else looking good to me

[giuppep]

Awesome! For some reason the multiple python version test strategy isn't working, because some of those optional parameter type hints should fail for 3.8. Everything else looking good to me

Should be fixed now 👍🏽

[Lxstr]

Has been merged into dev