Build out dev container

[dAdil]

Here, I add a few quality-of-life improvements to make the dev experience as smooth as possible:

• Install the psql CLI into the container.
• Install python requirements as part of container setup.
• Set port forwarding the recommended way (oops, I had that misconfigured before).
• Added a debugger configuration for vscode.
• Added a migration script to create the DB and auto-apply the relevant schema updates on launch.

All included, a new developer should now just have to open the repository in a dev container enabled vscode and hit run!

@SamP20 I'm not sure how the migration script would fit in with your DB dump + sample data? I presume we could start with an empty DB, run your SQL script, set the "last_migrated.txt" to migration/19_address_not_null and debug from there?

[dAdil]

This started life as a 1-liner and then grew. It should have probably become a python script as soon as I added statefulness via last_migrated.txt, but here we are :( If you feel strongly about it let me know and I'll convert it across.

[SamP20]

@SamP20 I'm not sure how the migration script would fit in with your DB dump + sample data? I presume we could start with an empty DB, run your SQL script, set the "last_migrated.txt" to migration/19_address_not_null and debug from there?

I'm wondering whether we should start using something like https://flask-migrate.readthedocs.io/en/latest/index.html? It stores the migration version in the database itself, ensuring the version always stays in sync. The easiest option would probably be to condense all our existing scripts into a single migration, then continue from there

I'm happy to use this script in the meantime though if it makes things a bit easier for you.

[dAdil]

Ooh, I like this idea - I haven't really worked in this stack before which is why I jumped at automating sql via bash. It probably makes sense for me to keep this PR open and move across to that over the next week or 2 rather than uproot everyone's dev process only to do it again in a few weeks time.

Sorry this isn't in the thread, I can't seem to reply to comments - only create new ones...

[dAdil]

Sorry for the delay! I had some time to work on this earlier this week, but got lost in a dependency versioning mess. I've pinned certain versions of the python dev container and the postgres images so that we can't mix up pgsql vs CLI versions when doing pg_dumps etc in future.

This PR is now a breaking change. If you have a DB already, you will need to do the following:

1. Ensure all of the the previous migrations were applied.
2. Checkout the latest change.
3. Gather the new python dependences (via pip, virtual environment, rebuilding dev container etc).
4. Run flask --app hackspace_mgmt db stamp head to apply the initial schema version change.
5. Start the app as usual.

I'm happy to be on hand during the real upgrade if we are concerned, but taking a backup and using that as a roll-back strategy is probably the safest bet.

[SamP20]

This is amazing work, thank you! I'll try and find some time to give it a proper review, especially the new migration.