[Readme Request] Add documentation on how to self host manually

[Ufinexa]

Would love to be able to host this separately onto a dedicated server as I attempted on Heroku and was told it goes against Salesforce's policy and trying Railway caused the connection to constantly drop. I'm not too sure how I would host this while I have an active domain and site available so any extra documentation for doing it manually and with my own domain would be greatly appreciated!