The users' show action URL is "domain.com/users/(:id)". How can I change this into "domain.com/(:id)"?

(I use devise if it does make any difference.)

I added this in my routes but it doesn't work.

```
 get '(:username)' => 'users#show'

```

Couldn't figure out how is this possible in the Rails Routing [guide](http://guides.rubyonrails.org/routing.html).

---

**Update**

I placed `get "/:username" => 'users#show'` at the bottom of my routes file. When I browse to `http://localhost:3000/testuser` I get this in my logs:

```
Started GET "/testuser" for 127.0.0.1 at 2014-03-27 12:05:32 +0000
Processing by UsersController#show as HTML
  Parameters: {"username"=>"testuser"}
  User Load (0.7ms)  SELECT "users".* FROM "users" WHERE "users"."username" IS NULL LIMIT 1
Redirected to http://localhost:3000/
Completed 302 Found in 5ms (ActiveRecord: 0.7ms)

```

testuser does exist. But for some reason is nul and redirects to homepage. If I try to go to `http://localhost:3000/users/testuser` the user's show action loads up fine.