User management module

User Management: Each user is associated with one group; one group can have multiple users. When user creates another user using user management, newly created user should be in same group as him. When new user has been created admin user can grant permission to newly created user so newly created user can only insert update those section of the app menu. Means user who has permission to add another user can create user who can have only event permission. So when newly created user will log in he can see only event menu on dashboard. (This is just for example, updating all existing module to have this kind of functionality will be in next module). Ok, at this point now we have various modules, users belongs to different groups and each user have permission to access specific modules. However, so far our app doesn’t use groups (except template module) and permissions. So during this phase what I need is to make all our module compatible with groups and permission.