test task

users table:
Table Users {
  Id,
  Name
}

1. Policies
an example of: 
reboot_system - "Allow user to reboot system", 
write_to_file - "Allow user write files", 
delete_files - "Allow user delete files", 
change_user_prefernces - "Allow user to edit other users"

Table Policies {
  Id,
  Name,
  Description
}

2. UserPolicies
Table UserPolicies {
  Id,
  UserId, // this is a foreign key to User
  PolicyId // this is a foreign key to Policy
}

3. Roles
Table Roles {
  Id,
  Type,
  PolicyId // this is a foreign key to Policy
}

4. UserRoles
Table UserPolicies {
  Id,
  UserId, // this is a foreign key to User
  RoleId // this is a foreign key to Role
}

5. Methods

function CreateUser('Andrew'): ObjectUser;
function CreatePolicy(write_to_file, "Allow user write files"): ObjectPolicy;
function CreateRole('moderator', ObjectPolicy): ObjectRole;
function SetRole(ObjectRole, ObjectUser): boolean;
function SetPolicy(ObjectPolicy, ObjectUser): boolean;
function DeleteRole(ObjectRole, ObjectUser): boolean;
function DeletePolicy(ObjectPolicy, ObjectUser): boolean;