defmodule Slax.Repo.Migrations.AlterUsersAddUsername do
  use Ecto.Migration

  def change do
    alter table(:users) do
      add :username, :citext
    end

    query = """
    update
      users
    set
      username = initcap(substring(email from '^[^@]+'))
    ;
    """

    execute query, ""

    alter table(:users) do
      modify :username, :citext, null: false, from: {:citext, null: true}
    end

    create unique_index(:users, :username)
  end
end