Easiest way to put chords in a post is to stick them in the text in brackets:

Happy(C)Birthday to(G)you etc

But the thing is, any one note will fit into lots of different chords, and some people like to put in more chords changes than others and we all sing songs in the keys that fit our voice and so forth. So there isn't any one "right" set of chords to a sing. (Mind, there isn't any one right set of words either, if it's been kicking around for a good few years...)

But now let's just try Homeless's recipe:

   G                  G 
  Ten years ago on a cold dark night 
             D       D7      C                   G 
  there was someone killed 'neath the town hall light.