Fix release link regex

* use %r
* don't capture groups since they are not used

app/models/releases/link.rb

@@ -6,7 +6,7 @@ module Releases
 
     belongs_to :release
 
-    FILEPATH_REGEX = /\A\/([\-\.\w]+\/?)*[\da-zA-Z]+\z/.freeze
+    FILEPATH_REGEX = %r{\A/(?:[\-\.\w]+/?)*[\da-zA-Z]+\z}.freeze
 
     validates :url, presence: true, addressable_url: { schemes: %w(http https ftp) }, uniqueness: { scope: :release }
     validates :name, presence: true, uniqueness: { scope: :release }