Use `%r{}` regexes to avoid having to escape `/`

app/validators/dynamic_path_validator.rb

@@ -104,7 +104,7 @@ class DynamicPathValidator < ActiveModel::EachValidator
   end
 
   def self.contains_path_part?(path, part)
-    path =~ /(.*\/|\A)#{Regexp.quote(part)}(\/.*|\z)/
+    path =~ %r{(/|\A)#{Regexp.quote(part)}(/|\z)}
   end
 
   def self.follow_format?(value)

spec/validators/dynamic_path_validator_spec.rb

@@ -63,13 +63,13 @@ describe DynamicPathValidator do
   # - Followed by one or more path-parts not starting with `:` or `*`
   # - Followed by a path-part that includes a wildcard parameter `*`
   # At the time of writing these routes match: http://rubular.com/r/Rv2pDE5Dvw
-  STARTING_WITH_NAMESPACE = /^\/\*namespace_id\/:(project_)?id/
-  NON_PARAM_PARTS = /[^:*][a-z\-_\/]*/
-  ANY_OTHER_PATH_PART = /[a-z\-_\/:]*/
-  WILDCARD_SEGMENT = /\*/
+  STARTING_WITH_NAMESPACE = %r{^/\*namespace_id/:(project_)?id}
+  NON_PARAM_PARTS = %r{[^:*][a-z\-_/]*}
+  ANY_OTHER_PATH_PART = %r{[a-z\-_/:]*}
+  WILDCARD_SEGMENT = %r{\*}
   let(:namespaced_wildcard_routes) do
     routes_without_format.select do |p|
-      p =~ %r{#{STARTING_WITH_NAMESPACE}\/#{NON_PARAM_PARTS}\/#{ANY_OTHER_PATH_PART}#{WILDCARD_SEGMENT}}
+      p =~ %r{#{STARTING_WITH_NAMESPACE}/#{NON_PARAM_PARTS}/#{ANY_OTHER_PATH_PART}#{WILDCARD_SEGMENT}}
     end
   end