Introduce group posts

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

priv/repo/migrations/20200717142633_rename_conversations_to_discussions.exs

@@ -0,0 +1,21 @@
+defmodule Mobilizon.Storage.Repo.Migrations.RenameConversationsToDiscussions do
+  use Ecto.Migration
+
+  def up do
+    rename(table("conversations"), to: table("discussions"))
+    rename(table("comments"), :conversation_id, to: :discussion_id)
+
+    alter table(:actors) do
+      add(:discussions_url, :string, null: true)
+    end
+  end
+
+  def down do
+    rename(table("discussions"), to: table("conversations"))
+    rename(table("comments"), :discussion_id, to: :conversation_id)
+
+    alter table(:actors) do
+      remove(:discussions_url)
+    end
+  end
+end