Update README for required software and installation guide especially the database.

[sampritavh]

This software requires a database to be available. I couldn't find the instructions in the README. It would be good if it can be included in the README as to what DBs are supported and the example DB Url expected for each type of DB.

[MarconLP]

There is a guide on how to setup a MySQL database on Railway, but we should probably also include steps to use a locally installed MySQL Database.

Snapify requires a MySQL database in the following format:

DATABASE_URL='mysql://root:password@127.0.0.1:3306/snapify'

[Dkingofcode]

Can i take this issue?