[zanata/zanata-client] a5879a: docs: add CONTRIBUTING.md

[GitHub]

  Branch: refs/heads/contributing
  Home:   https://github.com/zanata/zanata-client
  Commit: a5879a50a57b7756926694e2d40d265b6d85bf72
      https://github.com/zanata/zanata-client/commit/a5879a50a57b7756926694e2d40d265b6d85bf72
  Author: Ding-Yi Chen <dingyichen at gmail.com>
  Date:   2016-02-23 (Tue, 23 Feb 2016)

  Changed paths:
    A CONTRIBUTING.md

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