How to search User (Entity) columns without sec. index?

[Alan Ristić]

Here is the thing. I'm modelling User entity and got to problem with
searching trough user columns.

CREATE TABLE users (
  user_uuid uuid PRIMARY KEY,
  date_created timestamp,
  password varchar,
  username varchar,
  name varchar,
  first_name varchar,
  last_name varchar,
  email varchar,
  ...
) ;

CREATE INDEX users__username_idx ON users (username);

Now I know it's a bad practice to model sec. index on 'username' becouse of
uniqness and all but what's the alternative? I'd want 'username' to be
"searchable"?

Tnx,
*Alan Ristić*

*m*: 040 423 688