Add timezone handling

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

priv/repo/migrations/20211008084901_add_timezone_to_addresses.exs

@@ -0,0 +1,9 @@
+defmodule Mobilizon.Storage.Repo.Migrations.AddTimezoneToAddresses do
+  use Ecto.Migration
+
+  def change do
+    alter table(:addresses) do
+      add(:timezone, :string)
+    end
+  end
+end