Team Authorization via oAuth

[knowtheory]

This is a branch that sets up a lambda function which can accept authorization requests from Slack, and record authorization details for later use.

[chriszarate]

hold me closer oauth dancer

[knowtheory]

Quick rundown:

• Sequelize is an ORM. It uses bluebird promises.
• we're using the postgres backend for Sequelize.
• Sequelize has some CLI helpers and a default project layout (which we're defying a little)
• There's a lib/migrations and lib/models directory which contain what you think
• We have two models, Authorization and Team
• The index function is pretty minimalist, it was just a huge pain the ass to debug.
• The index function receives a code from an attempted Slack authorization via the API Gateway`
• The index function then makes a Request to slack to verify the authorization
• Slack returns back an authorization object which contains the tokens we want.
• We look up or create a record the team in question
• We then store the authorization (and there could be more than one authorization per team)
• And then we tell them they successfully added the bot.

IMPORTANT NOTE:

• Sequelize is a pain in the ass and requires us to close down the DB connection explicitly so that the Lambda function can exit gracefully (necessary so that the API Gateway knows what's up).

[chriszarate]

yayyyy awesome :+1:

[knowtheory]

Oh by the way, we're pinned to the 6.4.2 (rather than 7.x) of the pg package because of this issue: https://github.com/sequelize/sequelize/issues/8043