Upgrade mongo driver

[Rovel]

Upgrade db connector to work with Mongo Atlas:

• Upgrade to Mongo 4 (WARNING: need to test backwards compatibility with mongo 3)
• Change MONGO_URI to use only db string, collection name is in the file now

This is already working on a Mongo Atlas of my own. if you need any more info on how to setup please let me know

[vercel[bot]]

@Rovel is attempting to deploy a commit to the Rubynor Team on Vercel.

A member of the Team first needs to authorize it.