Figure out Cryptographically Secure Pseudo Random Generator on blockchain for Raffle model

## Overview

As a developer implementing the raffle model, we need to find a way to have pseudo randomness.

### Reference

Official statement of the problem of on-chain randomness with list of potential solutions:
https://github.com/ethereum/research/wiki/Problems#21-on-chain-random-number-generation-63

One potential solution:
https://www.randao.org/whitepaper/Randao_v0.85_en.pdf

[Chainlink](https://chain.link/)

### Questions
Is it possible to have randomness on-chain?
If not, what our off chain options?

### Assumptions

This is needed for the raffle model.
This is possible

### Acceptance

- A recommendation on next steps forward for using an existing randomness solution
- Summary of aspects of the researched solutions, why not the ones you didn't choose?
- If necessary, bootleg-specific implementation details

## Tasks

- Research
- Write