added ruby2.0 and re-arranged docker file
added ruby2.0 and re-arranged docker file

xcthulhu/codewars-runner,xcthulhu/codewars-runner,remotty/cdr,xcthulhu/codewars-runner,remotty/cdr,remotty/cdr,remotty/cdr,xcthulhu/codewars-runner,remotty/cdr,remotty/cdr,remotty/cdr,xcthulhu/codewars-runner