How to organize a document approval system?

Question

Ruby on Rails

Good afternoon!
I don’t know how to organize a system for coordinating documents, Google is silent on this topic for some reason there is very little information.
Who developed ERP, please help.
Task, the user creates a document and can send it to another user for approval, which in turn can reject or approve it, tell me which way to dig? or maybe there are open source projects or whatever it is called in English, requests like docflow document managing system lead nowhere

Answer 1

And what's the problem?
2 entities: User and Document. The Document has user_id (the one who created), receiver_id (the one who agrees), state (status, new, confirmed, declined). The user creates a document, assigns a recipient. The recipient opens the list of documents in which he is the recipient and changes the state of the document. State the user can change only to those documents in which he is a receiver.
You can add various other states, such as draft (draft), not_sent (the document is written, but not sent for approval), sent (sent for approval), etc.