use dai for staking token

[tonisives]

It is confusing that the staking.test.js has the DAI ERC20 variable, but DAI is actually not used in Staking. Currently staking and reward tokens are the same.

This pull request uses DAI as the staked token.

I used

const rewardToken = await ethers.getContract("RewardToken")
instead of
const rewardToken = await deployments.get("RewardToken")

because otherwise the deployemnt failed with unknown function rewardToken.approve

[PatrickAlphaC]

Actually, I think it would be better just to remove dai from the tests altogether, I like the reward token being the staked token as well.

What do you think?

[tonisives]

Yeah it would make sense to remove the unused DAI variable from staking.test.js.

Btw if we used DAI for staking, it would brake the frontend code as well. So better to keep it as it is.

[PatrickAlphaC]

@tonisives front end code? What front end code

[tonisives]

I referenced this repository from Chainlink workshop Build a Full Stack DeFi Application: Code Along

I think the frontend also uses RT for both staking and rewards, so DAI would not work there.

[tonisives]

I created another pull request that removes the unused DAI variable here

[PatrickAlphaC]

Thank you!!

Will close this one then.