Add BTC/GUSD and ETH/GUSD trading pairs for Gemini

[bryanroth]

User Story

As a user I want to be able to use the BTC/GUSD and ETH/GUSD trading pairs with Gemini schedules so I don’t have to convert GUSD to USD in order for a schedule to work.

Description

Both BTC/GUSD and ETH/GUSD are valid trading pairs in Gemini but don’t appear in the list of trading pairs when creating a schedule for Gemini.

[ShamanShaz]

That's an interesting bug. For some reason Gemini's API does not offer GUSD as a trading pair for any crypto.

I double checked to see if this was an error with new listings like Solano, Ray, etc but it seems not. Users are able to place orders for the new tokens via the API.

This might be an issue with the underlying ccxt library, I'll check in with them.

[bryanroth]

Yeah, I checked the ccxt library and it seems like these trading pairs are just not supported.

However, it looks like it's possible to convert GUSD to USD via the Gemini API. Check out the following link and scroll down to the "Convert GUSD to USD (For Automating Deposits)" section. This code does leverage the gemini-python library but you might be able to reuse the logic here to do the same thing in DCAStack.