Fix Permission denied (#1893)

* Revert "default user for workspace is laradock, so that owner of log file when running php artisan command doesn't change (#1875)"

This reverts commit 156d124db0.

* update document to inform user should add --user=laradock when exec into workspace, update sync.sh bash to exec into workspace with user laradock

workspace/Dockerfile

@@ -889,12 +889,12 @@ RUN php -v | head -n 1 | grep -q "PHP ${LARADOCK_PHP_VERSION}."
 #--------------------------------------------------------------------------
 #
 
+USER root
+
 # Clean up
 RUN apt-get clean && \
     rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/* && \
     rm /var/log/lastlog /var/log/faillog
 
-USER laradock
-
 # Set default work directory
 WORKDIR /var/www