It’s no surprise I like Ruby, and gofmt is a great idea I wish Ruby could enforce. Instead of forgetting to run it constantly, let’s have git run it. In your .git/hooks/pre-commit:

#!/usr/bin/env ruby
Dir["**/*.go"].each do |go|
  if File.basename(go) !~ /^_/
    puts "gofmt #{go}"
    system("gofmt -w=true #{go} && git add #{go}")
  end
end

Make sure you run chmod a+x on that hook too. Also, this will mess up any incremental commits with git add -p, but you can use git commit --no-verify to bypass the hooks if you need to.