Add rails-log-mode recipe

Emacs Major mode for viewing Rails log files

https://github.com/ananthakumaran/rails-log-mode

I'm not affiliated with the package, but I had this response when I inquired about
submitting the recipe: https://github.com/ananthakumaran/rails-log-mode/issues/1
Merge pull request #1629 from dgtized/rails-log-mode

Add rails-log-mode recipe