[#923] Nickname & email selection for external registrations, option to connect to existing account.

priv/repo/migrations/20190315101315_create_registrations.exs

@@ -2,7 +2,8 @@ defmodule Pleroma.Repo.Migrations.CreateRegistrations do
   use Ecto.Migration
 
   def change do
-    create table(:registrations) do
+    create table(:registrations, primary_key: false) do
+      add :id, :uuid, primary_key: true
       add :user_id, references(:users, type: :uuid, on_delete: :delete_all)
       add :provider, :string
       add :uid, :string