Introduce group posts

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

priv/repo/migrations/20200721131521_add_url_to_conversation.exs

@@ -0,0 +1,36 @@
+defmodule Mobilizon.Storage.Repo.Migrations.AddUrlToConversation do
+  use Ecto.Migration
+
+  def up do
+    # Just in case old name is used
+    drop_if_exists(constraint(:comments, :comments_conversation_id_fkey))
+    drop_if_exists(constraint(:comments, :comments_discussion_id_fkey))
+
+    alter table(:discussions, primary_key: false) do
+      remove(:id)
+      add(:id, :uuid, primary_key: true)
+      add(:url, :string, null: false)
+    end
+
+    alter table(:comments) do
+      remove(:discussion_id)
+      add(:discussion_id, references(:discussions, type: :uuid), null: true)
+    end
+  end
+
+  def down do
+    drop_if_exists(constraint(:comments, :comments_conversation_id_fkey))
+    drop_if_exists(constraint(:comments, :comments_discussion_id_fkey))
+
+    alter table(:discussions, primary_key: true) do
+      remove(:id)
+      add(:id, :serial, primary_key: true)
+      remove(:url)
+    end
+
+    alter table(:comments) do
+      remove(:discussion_id)
+      add(:discussion_id, references(:discussions, type: :serial), null: true)
+    end
+  end
+end