Deploy code from Bitbucket to EC2

I am using BitBucket for my Django project and EC2 for cloud servers. My objective is that when I push a commit to a branch, BitBucket will make a call on the hook and the hook will update the code in EC2.

So far, when I commit, the hook is called but the code isn't being updated on the server. In my understanding, this is to do with permissions in Linux/Ubuntu 14.04.

I have tried to follow the link from Brandon Summers and further refinement of the same by going here. But it still doesn't work.

With the first link, I get this in the log:

fatal: Not a git repository (or any of the parent directories): .git
fatal: Not a git repository (or any of the parent directories): .git
chmod: cannot access '.git': No such file or directory
[Thu Jul 30 18:21:05.106127 2015] [:error] [pid 9736] [client 131.103.20.165:42727] PHP Notice:  Undefined property: Deploy::$_data in /var/www/html/deploy_home.php on line 127

And the second link gives me this in console:

[Sat Aug 01 15:26:35.000824 2015] [:error] [pid 2447] [client 131.103.20.165:39102] PHP Warning:  file_put_contents(/var/log/deploy/deployments.log): failed to open stream: No such file or directory in /var/www/html/deploy_repo.php on line 144
[Sat Aug 01 15:26:35.000869 2015] [:error] [pid 2447] [client 131.103.20.165:39102] PHP Warning:  chmod(): No such file or directory in /var/www/html/deploy_repo.php on line 147
[Sat Aug 01 15:26:35.000924 2015] [:error] [pid 2447] [client 131.103.20.165:39102] PHP Warning:  file_put_contents(/var/log/deploy/deployments.log): failed to open stream: No such file or directory in /var/www/html/deploy_repo.php on line 152
[Sat Aug 01 15:26:35.001010 2015] [:error] [pid 2447] [client 131.103.20.165:39102] PHP Warning:  file_put_contents(/var/log/deploy/deployments.log): failed to open stream: No such file or directory in /var/www/html/deploy_repo.php on line 144
[Sat Aug 01 15:26:35.001034 2015] [:error] [pid 2447] [client 131.103.20.165:39102] PHP Warning:  chmod(): No such file or directory in /var/www/html/deploy_repo.php on line 147
[Sat Aug 01 15:26:35.001068 2015] [:error] [pid 2447] [client 131.103.20.165:39102] PHP Warning:  file_put_contents(/var/log/deploy/deployments.log): failed to open stream: No such file or directory in /var/www/html/deploy_repo.php on line 152
sh: 1: /usr/sbin/sendmail: not found

The second link's console output has something to do with unable to write to the log file but still the repo folder remains unchanged on EC2.

What am I missing here?