Add documentation about newrelic support
Add documentation about newrelic support

CHH/heroku-buildpack-php,mraymond/heroku-buildpack-php,CHH/heroku-buildpack-php,nsg/dokku-buildpack-picocms,AlphaStaxLLC/heroku-buildpack-php-custom,AlphaStaxLLC/heroku-buildpack-php-custom,bobmaerten/dokku-buildpack-php,jstacoder/heroku-buildpack-php-1,jstacoder/heroku-buildpack-php-1,penciu/apache,briankilgore/heroku-buildpack-php-prod,cachethq/cachet-buildpack,bobmaerten/dokku-buildpack-php,CHH/heroku-buildpack-php,nsg/dokku-buildpack-picocms,pierredup/packager-buildpack-php,penciu/apache,pierredup/packager-buildpack-php,stof/heroku-buildpack-php,ryosuzuki/php-buildpack,Scalingo/php-buildpack,OKAMca/heroku-buildpack-php,AlphaStaxLLC/heroku-buildpack-php-custom,Scalingo/php-buildpack,Jonatasmz/php-buildpack,Jonatasmz/php-buildpack,mraymond/heroku-buildpack-php,penciu/apache,OKAMca/heroku-buildpack-php,ryosuzuki/php-buildpack,OKAMca/heroku-buildpack-php,stof/heroku-buildpack-php,Scalingo/php-buildpack,stof/heroku-buildpack-php