[#923] Registration validations & unique index on [:user_id, :provider].

lib/pleroma/registration.ex

@@ -23,6 +23,7 @@ defmodule Pleroma.Registration do
   def changeset(registration, params \\ %{}) do
     registration
     |> cast(params, [:user_id, :provider, :uid, :info])
+    |> validate_required([:provider, :uid])
     |> foreign_key_constraint(:user_id)
     |> unique_constraint(:uid, name: :registrations_provider_uid_index)
   end

priv/repo/migrations/20190315101315_create_registrations.exs

@@ -12,5 +12,6 @@ def change do
     end
 
     create unique_index(:registrations, [:provider, :uid])
+    create unique_index(:registrations, [:user_id, :provider])
   end
 end