Add Docker integration for easy development

[xkons]

I've created a Dockerfile and docker-compose config where your local checkout of the OpcacheBundle is used inside the official symfony demo application.

This makes development easy as you can immediately see the result of any changes.

[coveralls]

Coverage remained the same at 96.764% when pulling 342cebfc52846f7eed710f1dd6be554d3d0bf1b5 on docker-container into c0e7c7400d40ff9da64c9855097f7581d731fcb9 on master.

[Matthimatiker]

@xkons Thanks for your effort!

Currently, when executing docker-compose up, the installer complains about a security violation. Could you have a look into that?

Any ideas how we can solve that problem in the future? There will always be vulnerabilities, but it would be great if that would not break the demo, so that we can choose the time for fixing the problem on our own.

Executing script cache:clear [OK]
Executing script assets:install --symlink --relative public [OK]
Executing script security-checker security:check [KO]
 [KO]
Script security-checker security:check returned with error code 1
!!  
!!  Symfony Security Check Report
!!  =============================
!!  
!!   // Checked file: /usr/app/opcachebundle/composer.lock
!!  
!!   [ERROR] 1 packages have known vulnerabilities.                                 
!!  
!!  symfony/http-foundation (v4.1.1)
!!  --------------------------------
!!  
!!   * CVE-2018-14773: CVE-2018-14773: Remove support for legacy and risky HTTP headers
!!     https://symfony.com/blog/cve-2018-14773-remove-support-for-legacy-and-risky-http-headers
!!  
!!   ! [NOTE] This checker can only detect vulnerabilities that are referenced in   
!!   !        the SensioLabs security advisories database. Execute this command     
!!   !        regularly to check the newly discovered vulnerabilities.              
!!  
!!  
Script @auto-scripts was called via post-install-cmd
ERROR: Service 'opcachebundle' failed to build: The command '/bin/sh -c composer create-project symfony/symfony-demo .' returned a non-zero code: 1