Rakefile in yaks-0.3.1 vs Rakefile in yaks-0.4.0.rc1

@@ -13,8 +13,9 @@
 require 'mutant'
 task :default => :mutant
 
 task :mutant do
   pattern = ENV.fetch('PATTERN', 'Yaks*')
-  result  = Mutant::CLI.run(%w[-Ilib -ryaks --use rspec --score 100] + [pattern])
+  opts    = ENV.fetch('MUTANT_OPTS', '').split(' ')
+  result  = Mutant::CLI.run(%w[-Ilib -ryaks --use rspec --score 100] + opts + [pattern])
   fail unless result == Mutant::CLI::EXIT_SUCCESS
 end