fix to backup and fix max client

Fix supervisord.conf file path

otherwise image ignores the supplied supervisord.conf

add pgadmin backup volumes

you can use backup files  in ${DATA_SAVE_PATH}/pgadmin-backup

in  this version, you can backup postgresql

add docs on running Laravel Dusk tests

[UPDATE] change config redis from docker compose to env

use openssh-client not  openssh*

add demo and  use  caddy example for laravel

https://hub.docker.com/r/abiosoft/caddy/~/dockerfile/

https://github.com/caddyserver/examples/blob/master/laravel/Caddyfile

* 'master' of https://github.com/laradock/laradock:
  update Install Symfony steps in the docs
  Update docker-compose.yml
  Update env-example
  Update Dockerfile-70
  fix rm error

Missing symfony variables in env-example and workspace. Added python as an option to workspace

Added missing symfony and python options to workspace

Added missing symfony install variable and added new python install variable

Add python option to workspace

fix php-worker build error

ERROR INFO:

Step 4/5 : RUN rm -r /var/lib/apt/lists/*
 ---> Running in 4a3aa49e0e6e
rm: can't remove '/var/lib/apt/lists/*': No such file or directory
ERROR: Service 'php-worker' failed to build: The command '/bin/sh -c rm -r /var/lib/apt/lists/*' returned a non-zero code: 1

* 'master' of github.com:laradock/laradock:
  format the readme.md file
  fix travis ci hugo job get "cannot create directory" error.
  fixed #1068
  update some `guide` format in the documentation

fix travis ci hugo job get "cannot create directory" error.

fixed #1068 drush need mysql-client installed