empty changeset with Ecto 2.0

empty.ex

#
# pre ecto 2.0
#

# web/models/user.ex
defmodule User do
  schema "users" do
    field :name
    field :email
  end
  
  def changeset(user, params \\ :empty) do
    user
    |> cast(params, [:name, :email])
  end
end

# web/controllers/user_controller.ex
defmodule UserController do
  def new(conn, _params) do
    changeset = User.changeset(%User{})
    render(conn, "new.html", changeset: changeset)
  end
end

#
# post ecto 2.0
#

# web/models/user.ex
defmodule User do
  schema "users" do
    field :name
    field :email
  end
  
  def changeset(user, params \\ :invalid) do
    user
    |> cast(params, [:name, :email])
    |> validate_required([:name, :email])
  end
end

# web/controllers/user_controller.ex
defmodule UserController do
  def new(conn, _params) do
    # option 1 - use Ecto.Changeset.change/
    changeset = Ecto.Changeset.change(%User{})
    
    # option 2 - special `empty_changeset/2` function in user.ex
    changeset = User.empty_changeset()
    
    render(conn, "new.html", changeset: changeset)
  end
end