Adding curl

[Maescool]

Hi,
Big fan of your images! <3

I wonder if you could install curl?
This is used for the triggers gitlab has, to trigger a build from a build
https://about.gitlab.com/2015/08/22/gitlab-7-14-released/

Thanks!

[sameersbn]

This image is meant to be a base image for your runners which means you use this image to base your runner images. As such in your runner image you can install any package you desire/

[sameersbn]

p.s. curl is being installed in the image.