Route#duplicate: Use `#slice!` instead of `#slice`

Johan suggested simplifying this method by changing the `slice` call:
http://api.rubyonrails.org/classes/Hash.html#method-i-slice-21

I had modified this to fix the whitespace while working on the `WayCost`
calculation function for `Chouette::Route`s, so don't really have a
brain cache hit on this code, but the change makes sense and seems to
work.

Refs #6095

1 files changed, 1 insertions, 2 deletions

diff --git a/app/models/chouette/route.rb b/app/models/chouette/route.rb
index 01358e8aa..4b1b88543 100644
--- a/app/models/chouette/route.rb
+++ b/app/models/chouette/route.rb
@@ -82,9 +82,8 @@ module Chouette
         'opposite_route_id' => nil,
         'name' => I18n.t('activerecord.copy', name: self.name)
       }
-      keys_for_create = attributes.keys - %w{id objectid created_at updated_at}
       atts_for_create = attributes
-        .slice(*keys_for_create)
+        .slice!(*%w{id objectid created_at updated_at})
         .merge(overrides)
       new_route = self.class.create!(atts_for_create)
       duplicate_stop_points(for_route: new_route)