Adding Indexing on foreign keys

## Description and Impact
It should hopefully make things faster

## Deploy Plan
Nothing to worry about

## Rollback Plan
* To roll back this change, revert the merge with: `git revert -m 1 MERGE_SHA` and perform another deploy.

## URLs
> Links to bug tickets or user stories.

## QA Plan
> Fill in scenarios below. Review [QA Best Practices](https://source.sportngin.com/page/show/1227795-qa-best-practices).

#### Risk Level:
- [X] Low
- [ ] Medium
- [ ] High

Rake app:hubstats:reset then check sequel pro to see indices?