feat: Slack pairings

[tarikeshaq]

fixes #514 , closes https://github.com/ubclaunchpad/ideas/issues/8

Details

Creates basic donut style matching for Rocket.

What implemented so far:

• A donut scheduler that currently runs every minute (for debugging purposes, will bump to a reasonable number once this is ready to land)
• Some initial refactoring to allow the schedulers to have access to the db
• Slack api calls needed to:
  • Get a slack channel's id by name
  • Create a private conversation given a list of users
• Basic persistence of pairings in a new pairings table

TODOs before this is ready:

• [x] Add persistence, to prevent users from getting matched again
• [x] ~~Add TTL to entries in the Pairings table~~ I can file a follow up for this, we can live without it for now
• [x] Add tests
  • For slack API calls
  • For persistence
• [ ] Add documentation
  • General documentation for the feature
  • For the new environment variable
  • Documentation for the new pairings table

Where I am currently:

~~Contemplating if I should add a table for the pairings or if it should be a part of the User model, leaning towards the latter with possibly opening a ticket for the former beyond this pr. Went with creating a new table 😄 Now working on adding the TTL and making sure edge cases don't explode on us~~

I'll be updating the above as I go.

[bobheadxi]

[chuck-sys]

Contemplating if I should add a table for the pairings or if it should be a part of the User model, leaning towards the latter with possibly opening a ticket for the former beyond this pr.

IMO I think you should go with the former (though the difference in work is pretty significant). Seems less hacky and wouldn't leak too much information (example: /rocket user view can potentially see who you matched with).

And it would set the precedent for similar things in the future.

[codecov[bot]]

Codecov Report

Merging #553 into master will decrease coverage by 0.54%. The diff coverage is 83.52%.

@@            Coverage Diff             @@
##           master     #553      +/-   ##
==========================================
- Coverage   93.01%   92.46%   -0.55%     
==========================================
  Files          42       44       +2     
  Lines        2420     2589     +169     
  Branches      323      346      +23     
==========================================
+ Hits         2251     2394     +143     
- Misses        110      131      +21     
- Partials       59       64       +5     

Impacted Files	Coverage Δ
db/dynamodb.py	85.71% <57.14%> (-4.80%)	:arrow_down:
app/model/pairing.py	65.00% <65.00%> (ø)
tests/memorydb.py	91.17% <76.92%> (+1.06%)	:arrow_up:
app/scheduler/__init__.py	92.30% <80.00%> (-2.94%)	:arrow_down:
interface/slack.py	95.77% <87.50%> (-2.41%)	:arrow_down:
app/model/__init__.py	100.00% <100.00%> (ø)
app/scheduler/modules/pairing.py	100.00% <100.00%> (ø)
config/__init__.py	100.00% <100.00%> (ø)
db/facade.py	100.00% <100.00%> (ø)
... and 2 more

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[tarikeshaq]

OK I got some time to work on this again (after like 20 days 😢) and Added a few tests.

I think this is ready for a round of review so I'll change it from a draft. My next focus will be docs and addressing any feedback that pops up. No rush on the review, we are all busy and this is decently large.

[bobheadxi]

[bobheadxi]

Nothing that this closes https://github.com/ubclaunchpad/ideas/issues/8 as well