Merge pull request #9785 from stanley-cheung/php-update-doc

PHP: added README notes for RHEL 6/7 users

src/php/README.md

@@ -13,12 +13,24 @@ shared C library.
 * `phpunit` (optional)
 
 **Install PHP and PECL on Ubuntu/Debian:**
+
+For PHP5:
+
 ```sh
-$ sudo apt-get install php5 php5-dev php-pear
+$ sudo apt-get install php5 php5-dev php-pear phpunit
+```
 
-OR
+For PHP7:
+
+```sh
+$ sudo apt-get install php7.0 php7.0-dev php-pear phpunit
+```
 
-$ sudo apt-get install php7.0 php7.0-dev php-pear
+**Install PHP and PECL on CentOS/RHEL 7:**
+```sh
+$ sudo rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
+$ sudo rpm -Uvh https://mirror.webtatic.com/yum/el7/webtatic-release.rpm
+$ sudo yum install php56w php56w-devel php-pear phpunit gcc zlib-devel
 ```
 
 **Install PECL on Mac:**
@@ -52,6 +64,10 @@ This will compile and install the gRPC PHP extension into the standard PHP
 extension directory. You should be able to run the [unit tests](#unit-tests),
 with the PHP extension installed.
 
+Note: For users on CentOS/RHEL 6, unfortunately this step won't work. Please
+follow the instructions below to compile the extension from source.
+
+
 **Update php.ini**
 
 Add this line to your `php.ini` file, e.g. `/etc/php5/cli/php.ini`