Dockerfile converted to Alpine Linux based image and PHP7

[eniac111]

I made an image based on Alpine Linux with PHP7. Memcached is missing for now because it's unstable for php7.

[pierreozoux]

Thanks a lot for your PR.

I'm currently waiting docker to review the current code to make it an official image.

Once this is done, we can start to add different tags (alpine and apache).
For that to work, we'd need some rework on the repo to have a folder architecture that would look like WordPress for instance.

I think the target would be to have 3 tags:

• apache
• fpm
• alpine-fpm

If you can rework your PR to tend to this goal, this would facilitate a lot our work!

Thanks!

[eniac111]

Of course, I'll give it some time in the weekend.
Btw, I noticed a bug in this image today. Don't merge it for now.