Add foreign_key_constraint validation to Article and Translation

lib/outlook/articles/article.ex

@@ -23,5 +23,6 @@ defmodule Outlook.Articles.Article do
     article
     |> cast(attrs, [:title, :content, :url, :language, :date, :author_id])
     |> validate_required([:title, :content, :url, :language, :date, :author_id])
+    |> foreign_key_constraint(:author_id)
   end
 end

lib/outlook/translations/translation.ex

@@ -29,5 +29,6 @@ defmodule Outlook.Translations.Translation do
     |> unique_constraint([:lang, :article_id],
         message: "translation for this language already exists",
         name: :article_id_lang_unique_index)
+    |> foreign_key_constraint(:article_id)
   end
 end