[Feature] HackerTable & JudgeTable collections

[surbhi-gulati]

Ticket 7: design doc -- judging algo refresh

Expand our MongoDB and our node server to implement the HackerTable & JudgeTable collections, which our UI requires. You can use the work built in tickets 4-6 as an example for what this entails.

• For both collections, you will need to create new files in the data folder:

1. Schema
2. Model
3. DAO
4. Controller

• Note: the following 5 DAO/ controller functions are required for both collections

1. Create
2. Read (by ID, by name, all)
3. Delete all

• Add test files for all other operations

Reviewers: @mike10911 @kzeng24 @surbhi-gulati