Invitation System - Design Help for Newbie

Hello there,

I just started a project using RoR. Was a C# / .NET programmer before
jumping into this project.

Here's my project's details:

Architect a website that has users, projects, events, and groups. The
site has a simple invitation system. Any user can be part of a
project, an event, or a group. Users, Projects, events, and groups
don't need to contain any information and could just be a primary key
(keep things very basic). Come up with a way to model this in the
database and in your model.

Add the ability to send a note along with an invitation (the note is
attached to the invitation). Set up some test data for users,
projects, events, and groups then create control logic for a user to
invite another user to projects, events, and groups. The output of
the invite could be as simple as 'user 5 has invited user 1 to project
3 – “this is my test note”' or 'user 2 has invited user 3 to event 1
– “hey join my project”'.


(1) How would the database look if there was a way for users to accept
an invite to a group, event, project?

(2) Is the ability to add notes (text) with an invitation easy using

(3) What would be the best way to go about this?

Any help, tips and suggestions are greatly appreciated!