$ git push heroku master显示如下提示：
Permission denied (publickey).
fatal: Could not read from remote repository. Please make sure you have the correct access rightsand the repository exists.
你需要将公钥同步到Heroku上：
$ heroku keys:add ~/.ssh/*.pub
如果没有，那么heroku会提醒你新建一个公钥用：
heroku keys:add