Permissions module

Database tables: 

Users {
 id
 name
}

Roles {
 id
 name
 description
}

UserRoles {
 id
 user_id
 role_id
}

Permissions {
 id
 name
 type
}

RolePermission {
 id
 role_id
 permission_id
}

UserPermission {
 id
 user_id
 permission_id
}


A list of functions:

 ## Grant permissions to user via role
function RegisterRole(name, description)
function GrantPermission(role, name, type)
function AssignRoleToUser(user, role)

 ## Grant permissions to a user
function GrantPermission(user, name, type)

 ## Check permission
function CheckPermission(User, permission_type)