Defines helpers to work with changeset.

Add a using statement use Waffle.Ecto.Schema to the top of your ecto schema, and specify the type of the column in your schema as MyApp.Avatar.Type.

Attachments can subsequently be passed to Waffle's storage though a Changeset cast_attachments/3 function, following the syntax of cast/3.

Example

defmodule MyApp.User do
  use MyApp.Web, :model
  use Waffle.Ecto.Schema

  schema "users" do
    field :name,   :string
    field :avatar, MyApp.Uploaders.AvatarUploader.Type
  end

  def changeset(user, params \\ %{}) do
    user
    |> cast(params, [:name])
    |> cast_attachments(params, [:avatar])
    |> validate_required([:name, :avatar])
  end
end