Supporting private repositories

[jeyemwey]

Hi,
thank you for the tool.
I want to use it for deploying my blog which is mirrored at a private GitHub repo. I can clone the repository with git clone https://jeyemwey:MYWEIRDPASSWORD@github.com/jeyemwey/blog just fine, however the container does not like it:

root@iamjannik.me /tmp $ docker run -it \
  -e "HTTP_USER=github" \
  -e "HTTP_PASS=abc" \
  -e "REPO_URL=https://jeyemwey:MYWEIRDPASSWORD@github.com/jeyemwey/blog" \
  -p 8081:80 \
  mikroways/jekyll

Secret to send posts with: cYSFjg4-esg8Wyxd9Mg-9Ab-Q3wZNbD_i-NWbLT7kF2DpmKvt_jVWfATtI5VQgIY
sed: -e expression #1, char 40: unknown option to `s'

I suppose, it's because of this line in the entrypoint.sh script which does not like the @ or the : in the REPO_URL variable.

I will try to fix that stuff and send a PR soon.