initial work on fixing user tests

test/support/fixtures/accounts_fixtures.ex

@@ -6,9 +6,11 @@ defmodule PokemonCouture.AccountsFixtures do
 
   def unique_user_email, do: "user#{System.unique_integer()}@example.com"
   def valid_user_password, do: "hello world!"
+  def unique_username, do: "user#{System.unique_integer()}"
 
   def valid_user_attributes(attrs \\ %{}) do
     Enum.into(attrs, %{
+      username: unique_username(),
       email: unique_user_email(),
       password: valid_user_password()
     })