Introduce group basic federation, event new page and notifications

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

test/support/conn_case.ex

@@ -25,7 +25,9 @@ defmodule Mobilizon.Web.ConnCase do
   using do
     quote do
       # Import conveniences for testing with connections
-      use Phoenix.ConnTest
+      import Plug.Conn
+      import Phoenix.ConnTest
+
       import Mobilizon.Web.Router.Helpers
 
       # The default endpoint for testing