mutant.rake in reek-4.0.5

- old
+ new

@@ -1,5 +1,18 @@
 desc 'Runs mutant'
 task :mutant do
-  system 'RUBY_THREAD_VM_STACK_SIZE=64000 bundle exec mutant --include lib '\
-         "--require reek --use rspec --since master --jobs 4 'Reek*'"
+  command = <<-EOS
+    branch_name=$(git symbolic-ref HEAD 2>/dev/null | cut -d"/" -f 3)
+    if [ "$branch_name" != "master" ]; then
+      RUBY_THREAD_VM_STACK_SIZE=64000\
+      bundle exec mutant\
+        --include lib\
+        --require reek\
+        --use rspec\
+        --since master\
+        --jobs 4 'Reek*'
+    else
+      echo "!!! Not running mutant on master branch !!!"
+    fi
+  EOS
+  system command
 end