Add getting started section to README

[rootulp]

Resolves #106

I needed to do these three steps to be able to run yarn in this package. Without these steps, I encountered:

$ npx hardhat compile
Error HH8: There's one or more errors in your config file:

  * Invalid value {"url":"https://kovan.infura.io/v3/undefined","accounts":["0xundefined"]} for HardhatConfig.networks.kovan - Expected a value of type HttpNetworkConfig.
  * Invalid value {"url":"https://mainnet.infura.io/v3/undefined","accounts":["0xundefined"]} for HardhatConfig.networks.staging_mainnet - Expected a value of type HttpNetworkConfig.
  * Invalid value {"url":"https://mainnet.infura.io/v3/undefined","accounts":["0xundefined"]} for HardhatConfig.networks.production - Expected a value of type HttpNetworkConfig.

To learn more about Hardhat's configuration, please go to https://hardhat.org/config/

[bweick]

This is good! One thing I'd add though is the error you got there seems to be related to a bad infura value? Alchemy is required for mainnet fork testing.

Did putting in an Alchemy key help solve this error? Maybe we can expand the steps to include getting an infura key?

[rootulp]

Did putting in an Alchemy key help solve this error?

Yep. Although agreed with your call out that the error explicitly states Infura so I'm not sure why my .env without a valid Infura token no longer encounters this error. I definitely don't mind adding steps for Infura as well. Will follow up with another commit