ElasticSearch synonym tokenization with Searchkick gem

searchkick_ext.rb

require 'searchkick'

module SearchkickSyn
  def searchkick_index_options
    # fetch index options
    options = super

    # inject Synonym filter for default index and searchkick search
    options[:settings][:analysis][:analyzer][:default_index][:filter].push "synonym"
    options[:settings][:analysis][:analyzer][:searchkick_search][:filter].push "synonym"

    # inject WordNet synonym filter
    options[:settings][:analysis][:filter][:synonym] = {
      :type => 'synonym',
      :synonyms_path => '/var/lib/wn_s.pl'
    }
    
    options
  end
end


# This is the 'footprint' definition (including all containing
# modules, etc.) of the class we want to 'prepend' with our module
module Searchkick
  module Reindex
  
    # This is the line where all the magic happens - we 'prepend'
    # the module we created above into the class
    prepend SearchkickSyn
  end
end

This only works on Ruby 2+

Is it possible to put the wordnet file inside the rails project itself? Not sure Heroku gives access to the var/lib folder.