webring/apps/webring/priv/repo/migrations/20221107231825_create_users.exs

defmodule Webring.Repo.Migrations.CreateUsers do
  use Ecto.Migration

  def change do
    create table "users" do
      add :username, :string
      add :hashed_password, :string
      timestamps() 
    end

    create unique_index(:users, [:username])
  end
end