various changes to make the image more focused and concise

Hi Thierry,

I made some changes to make your docker image - from my perspective - more focused to the task. Further php dependencies can easily be added by creating a very small Dockerfile inheriting from this. I don't wanna comment on everything, just a few remarks:

*   debian instead of ubuntu, because it's dockers choice for most base images, also it's really tiny
*   COPY > ADD (see bestpractices)
*   They have the concept of an entrypoint which allows us to either run nginx or any other command given by the user. We don't need ssh anymore.

Are you interested in merging this? Otherwise I'd just maintain this independently.

Tim
Good point (all the stuff that happened must have been composer, didn’t notice). Any remarks besides that? Sounds to me as if you’re not generally averse to my proposal.

> Am 03.11.2014 um 18:51 schrieb Thierry Thuon <notifications@github.com>:
> 
> In Dockerfile:
> 
> >  
> >  MAINTAINER Thierry Piaf <thierry@piaf.eu>
> >  
> > -RUN apt-get update && apt-get upgrade -y
> > -RUN apt-get install -y openssh-server htop vim
> > -RUN apt-get install -y curl htop nginx php5-fpm mongodb php5-imagick php5-gd curl php5-mongo php5-cli php5-curl php5-mcrypt php5-intl php5-xdebug
> to run php command (like php app/console), you need php5-cli
> 
> —
> Reply to this email directly or view it on GitHub <https://github.com/lepiaf/docker-symfony2/pull/1/files#r19750355>.
>