Spec improvements

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/mobilizon/actors/member/metadata.ex

@@ -0,0 +1,27 @@
+defmodule Mobilizon.Actors.Member.Metadata do
+  @moduledoc """
+  Represents metadata on a membership
+  """
+
+  use Ecto.Schema
+  import Ecto.Changeset
+
+  @type t :: %__MODULE__{}
+
+  @required_attrs []
+
+  @optional_attrs []
+
+  @attrs @required_attrs ++ @optional_attrs
+
+  embedded_schema do
+    # TODO : Use this space to put notes when someone is invited / requested to join
+  end
+
+  @doc false
+  @spec changeset(t | Ecto.Schema.t(), map) :: Ecto.Changeset.t()
+  def changeset(schema, params) do
+    schema
+    |> cast(params, @attrs)
+  end
+end