Community platform with paying options

Introduction
In this learning project we would like to set up a functional design for a system that can be used by communities.

Userstory

 * As an admin I'm able to create a closed group where people have to pay a monthly fee to get an invite.
 * As a user I can create projects and tasks. If somebody executes the task he/ she gets paid.
 * To make it very easy to start a new group. In the first three years you only pay a percentage of the montly fee.

Companies

 * Bunq:
 * Crowded:
 * Part-up: