Refactoring README.md

[w-masahiro-ct]

I have refactored the README.md.
Single quote and 2 space indent are common conventions in Ruby.

[gjtorikian]

I know it’s conventional in Ruby, but I am old school; for me, ' will always mean a single 'c'har while ” is for an entire ”string”. So, I cannot accept those changes.

[w-masahiro-ct]

OK, then I'll fix to be consistent with double quotes.

[gjtorikian]

Thank you!