Introduce group basic federation, event new page and notifications

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

priv/repo/migrations/20200410100554_add_number_edits_to_comment.exs

@@ -0,0 +1,9 @@
+defmodule Mobilizon.Storage.Repo.Migrations.AddNumberEditsToComment do
+  use Ecto.Migration
+
+  def change do
+    alter table(:comments) do
+      add(:edits, :integer, default: 0)
+    end
+  end
+end