text: -- user.roles
  CREATE TABLE public."user.roles" (
  	id serial NOT NULL,
  	role_name varchar(20) NOT NULL,
  	description text NULL,
  	CONSTRAINT user_roles_pk PRIMARY KEY (id),
  	CONSTRAINT user_roles_un UNIQUE (role_name)
  );
  COMMENT ON TABLE public."user.roles" IS 'User role table';
  
  
  -- users 
  CREATE TABLE public.users (
  	id uuid NOT NULL,
  	username varchar(30) NOT NULL,
  	first_name varchar(30) NOT NULL,
  	last_name varchar(30) NULL,
  	email varchar(100) NOT NULL,
  	active bool NOT NULL DEFAULT false,
  	role_id smallint null,
  	CONSTRAINT users_pk PRIMARY KEY (id),
  	CONSTRAINT users_un_uname UNIQUE (username),
  	CONSTRAINT users_un_email UNIQUE (email),
  	CONSTRAINT users_role_fk FOREIGN KEY (role_id) REFERENCES public."user.roles"(id) ON DELETE SET NULL ON UPDATE CASCADE
  	
  );
  COMMENT ON TABLE public.users IS 'User account';
  
  
  -- insert initial data to 'user.roles'
  INSERT INTO "user.roles" (name, description)
  VALUES
      ('Superuser', 'Super admin'),
      ('Admin', 'Administrator');
  