added a custom rubocop linter in order to avoid hardcoding application name

lib/cops/application_name.rb

@@ -0,0 +1,17 @@
+if defined?(RuboCop)
+  module RuboCop
+    module Cop
+      module DS
+        class ApplicationName < Cop
+          MSG = "Avoid hardcoding `demarches-simplifiees.fr`. Instead use a dedicated environnement variable."
+
+          def on_str(node)
+            return unless node.source.include?('demarches-simplifiees.fr')
+
+            add_offense(node)
+          end
+        end
+      end
+    end
+  end
+end