Swap databases with a single config change

[mjewell]

No description provided.

[mjewell]

Hey, I was thinking more about the way databases are used and it still seemed kinda awkward to add support for new databases, as well as to switch between them. I took a shot at getting it to work where all you have to change is the DB_TYPE env variable and the server will figure out what stuff it should support based on that. The main point is that now there is a DB folder in the server which contains all the database/ORM specific code, including:

• models
• controllers
• deserializing users
• connecting to the database
• session stores
• passport logic

As a result, if you want to add a new database like I did/would do for the Postgres change, all the associated code goes to a single place with no changes required in the main server logic. Additionally, the server can handle incremental changes: if you just want your new database to support users but not topics, just define controllers/users.js. Don't care about google-oauth? Don't bother implementing passport/google.js

I think it helps to get a little closer to #156, but any feedback is appreciated

[choonkending]

@mjewell This is a very good abstraction.

The main point is that now there is a DB folder in the server which contains all the database/ORM specific code,

I believe this is the way forward. I will pull and test and hopefully merge this in today. Thanks very much for this!

[choonkending]

👍 I really appreciate your help with this change! Merged!