[zanata/zanata-server] 435b4d: docs: add CONTRIBUTING.md

[GitHub]

  Branch: refs/heads/contributing
  Home:   https://github.com/zanata/zanata-server
  Commit: 435b4dff00dc98502b7170d067700e6f2acaaacc
      https://github.com/zanata/zanata-server/commit/435b4dff00dc98502b7170d067700e6f2acaaacc
  Author: Ding-Yi Chen <dingyichen at gmail.com>
  Date:   2016-02-23 (Tue, 23 Feb 2016)

  Changed paths:
    M CONTRIBUTING.md

  Log Message:
  -----------
  docs: add CONTRIBUTING.md