Put IntegerNumberChamp behind a flag

config/features.rb

@@ -15,6 +15,8 @@ Flipflop.configure do
       title: "Champ double menu déroulant"
     feature :champ_carte,
       title: "Champ Carte"
+    feature :champ_integer_number,
+      title: "Champ nombre entier"
   end
 
   feature :web_hook