Add support for Docker

[LeviPesin]

Please add support for Docker and please add an official Docker image for NGINX Extras (that installs NGINX or NGINX-Mod and configures repositories).

[dvershinin]

I don't see how this fits the project. NGINX Extras is mostly about RPM packages.
Docker is "another packaging method", that is entirely out of scope (distro-specific packages being the main scope).
Care to elaborate?

[LeviPesin]

I meant creating an image like GetPageSpeed/nginx that installs nginx or nginx-mod and configures repositories. So something like will work out of the box:

FROM GetPageSpeed/nginx

RUN yum -y install nginx-some-extra-module && yum -y clean all && rm -rf /var/cache

And GetPageSpeed/nginx also could be used as a standalone image.

[dvershinin]

@LeviPesin Just to clarify, our RPM repository is available by subscription only, so I'm not sure if hosting a Docker image of our packages on Docker Hub would be in line with that. If you meant to use our packages through a subscription, I'd be happy to help you get set up. But if you meant to use our packages for free through a Docker image, I'm afraid that might not be possible.

[LeviPesin]

I'm not sure if hosting a Docker image of our packages on Docker Hub would be in line with that.

But if I understand correctly, the subscription is applied only when a package from the NGINX Extras repository is installed, not when this repository itself is first configured on the system?
So the base GetPageSpeed/nginx image (hosted publicly on Docker Hub) won't use anything that goes beyond the usage without subscription -- but when a user wants to install a nginx-extra package, they must build themselves a new Docker image (hosted privately) based on GetPageSpeed/nginx (like described in #16 (comment)), and then they will be required to have a subscription (because otherwise they will not be able to install the nginx-extra package during the build).