[#923] Support for multiple (external) registrations per user via Registration.

lib/pleroma/registration.ex

@@ -0,0 +1,36 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Registration do
+  use Ecto.Schema
+
+  import Ecto.Changeset
+
+  alias Pleroma.Registration
+  alias Pleroma.Repo
+  alias Pleroma.User
+
+  schema "registrations" do
+    belongs_to(:user, User, type: Pleroma.FlakeId)
+    field(:provider, :string)
+    field(:uid, :string)
+    field(:info, :map, default: %{})
+
+    timestamps()
+  end
+
+  def changeset(registration, params \\ %{}) do
+    registration
+    |> cast(params, [:user_id, :provider, :uid, :info])
+    |> foreign_key_constraint(:user_id)
+    |> unique_constraint(:uid, name: :registrations_provider_uid_index)
+  end
+
+  def get_by_provider_uid(provider, uid) do
+    Repo.get_by(Registration,
+      provider: to_string(provider),
+      uid: to_string(uid)
+    )
+  end
+end