add GITLAB_CI_HOST

Do not overwrite app_config["production"]["gitlab_ci"], but only edit app_config["production"]["gitlab_ci"]["host"] and app_config["production"]["gitlab_ci"]["https"] if necessary.

Rename GITLAB_HTTPS to GITLAB_CI_HTTPS, add GITLAB_CI_HOST
Merge pull request #2 from truongsinh/patch-2

add GITLAB_CI_HOST, rename GITLAB_HTTPS to GITLAB_CI_HTTPS