Enable extra if the GridWeapon is in position 9, 10, 11

app/controllers/api/v1/grid_weapons_controller.rb

@@ -140,6 +140,9 @@ module Api
         if weapon.position == -1
           party.element = weapon.weapon.element
           party.save!
+        elsif [9, 10, 11].include?(weapon.position)
+          party.extra = true
+          party.save!
         end
 
         # Render the weapon if it can be saved