Medium Article: Medium Article: Building Many-to-Many Associations with cast_assoc and Nested Forms in Phoenix and Ecto

registration_controller.ex

defmodule Class.RegistrationController do
  # ...
  
  def create(conn, %{"account" => params}) do
    changeset = Account.changeset(%Account{}, params)
    case Repo.insert(changeset) do
      {:ok, account} ->
        redirect conn, to: registration_path(conn, :new)
      {:error, changeset} ->
        changeset = %{changeset | action: :insert}
        render conn, "new.html", changeset: changeset
    end
  end
end