Add an example of installing "redis" and "xdebug" from PECL (PHP 7.1 compatible)
Add an example of installing "redis" and "xdebug" from PECL (PHP 7.1 compatible)

infosiftr/docker-library-docs,avoinea/docs,ceejatec/docs,nats-io/docker-docs,docker-flink/docs,vmassol/docs,gprivitera/docs,gprivitera/docs,davidcurrie/docs,vmassol/docs,Lightstreamer/docs,zendtech/docs,tilosp-docker/library-docs,tilosp-docker/library-docs,docker-solr/docs,odoo/docker-docs,crate/docker-docs,dinogun/docs,odoo/docker-docs,31z4/docs,car031/docs,nats-io/docker-docs,infosiftr/docker-library-docs,docker-library/docs,Lightstreamer/docs,ceejatec/docs,jetty-project/docker-docs,dmetzler/docker-library-docs,docker-library/docs,31z4/docs,davidcurrie/docs,docker-solr/docs,car031/docs,zendtech/docs,docker-flink/docs,avoinea/docs,Bonitasoft-Community/docker_docs,dinogun/docs,Bonitasoft-Community/docker_docs,jetty-project/docker-docs,dmetzler/docker-library-docs,crate/docker-docs