API TODOs

- [ ] Create Database to save snapshot, period and user data.
- [ ] Simple authentication for endpoints.
- [ ] Button for admin to take a hidden snapshot for each week and publishing results at the end of the week. Rewards for each user must be calculated based on the amount of NEC given per week.
- [ ] Calculate APY.
- [ ] Simple UI for admin.

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- [x] Cleanup the code
- [x] Verify restrictions in controllers:
* Periods cannot be created before the end date of the last week registered
* Snapshots cannot be taken more than once on the same week
* Fetched rewards filtered by address cannot show bpt_balance or nec_earned until week has closed field as true
* Fetched rewards filtered by address must be only from current period
- [x] Endpoint to fetch last period's end date
- [x] Endpoint to fetch if snapshot has been taken this week
- [x] Cron to verify at the end of each week (around sunday evening) if the current week's snapshot has been taken. If not, take it and publish results. If taken, publish results. Cron should also verify if the current week is part of a period.
- [ ] Fix admin ui styles
- [ ] Incorporate admin UI error messages
- [x] Get NEC and BPT price in USD
- [ ] Calculate APY with values above
- [ ] Make latest UI changes to contemplate that REP rewards were eliminated

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- [ ] Save unlocking date and contract address to the DB when it deploys in the CRON.
- [ ] Make admin endpoints and buttons to download all snapshots, and this week/period snapshot.
- [ ] Fix the weeks without rewards for user's address not appearing