Just normalize your model properly:
create table user_rank
(
id integer primary key, -- no identity, so you can control the values
rank varchar(20) not null unique
);
insert into user_rank (id, rank)
values
(1, 'Fresh Meat'),
(2, 'Intern'),
(3, 'Janitor'),
(4, 'Lieutenant'),
(5, 'Supreme being');
CREATE TABLE [users]
(
ID INT NOT NULL IDENTITY(1,1) PRIMARY KEY,
username varchar(255),
password varchar(255),
mail varchar (255),
rank integer not null default 1,
constraint fk_user_rank foreign key (rank) references user_rank (id)
);
I hope this helps you.
Get a further understanding from the Microsoft SQL course