Add PostgreSQL migration

[GetPsyched]

As of now, when a local instance of this project is run, it assumes that your database has been set with the right schema.

The migration is currently done in Project-Hyperlink. However, I do not want to re-write this exact code in Go. Rather, if possible, it will be better to integrate an optional argument migrate when running go run cmd/main.go which will execute this piece of code and migrate the given PostgreSQL database to our set schema.

This will make it easier to run and debug a local instance of Postgres which as of now is not possible automatically.

Optionally, the implementation of this in Project-Hyperlink can be removed entirely and fetched from a hosted instance of this repository instead. This will be better as otherwise the schemas will need to be updated in both repositories for no good reason.

[GetPsyched]

Remaining in this issue is to have the option to migrate on command and not on every run of this repo's instance