Rakefile in polymer-1.0.0.beta.6 vs Rakefile in polymer-1.0.0.beta.7

@@ -19,10 +19,10 @@
 
 # --- Build ------------------------------------------------------------------
 
 desc 'Build the gem, and push to Github'
 task :release => :build do
-  unless system('git branch') =~ /^\* master$/
+  unless `git branch` =~ /^\* master$/
     puts "You must be on the master branch to release!"
     exit!
   end
 
   sh "git commit --allow-empty -a -m 'Release #{Polymer::VERSION}'"