Add platform specific notes to installation

Author: Borys Belinsky

source/.res/list.supported-platform.rpm.txt

@@ -1,5 +1,9 @@
 
-- |rhel| 6 (Current Stable)
 - |centos| 7 and |rhel| 7
 - |rhel| 8
 
+
+Also it is needed to mention that on centos7 it is needed to install epel-release package and enable epel repo
+On debian9 it is needed to enable llvm repo as for now we haven't rebuilt llvm
+Here are there instructions how to enable llvm repo:
+https://apt.llvm.org/

source/installing.rst

@@ -13,17 +13,24 @@ Like many other |percona| products, |pdp| is installed by using the
 |percona-release| utility. As soon as it is ready, enable |pdp| and then install
 using the commands of your package manager.
 
-Make sure to run |percona-release| as root or via |sudo|. For convenience, all
-commands that require elevated priviges start with |sudo|.
+.. important::
 
-.. code-block:: bash
+   Before you attempt to install |pdp|, update |percona-release| to its latest
+   version. For the steps described in this section to succeed,
+   |percona-release| must be version 1.0.12 or later.
 
-   $ sudo percona-release enable experimental ppg-11
+   .. seealso::
+
+      Documentation of |percona-release|
+         https://www.percona.com/doc/percona-repo-config/percona-release.html
 
-.. seealso::
 
-   Documentation of |percona-release|
-      https://www.percona.com/doc/percona-repo-config/percona-release.html
+Make sure to run |percona-release| as root or via |sudo|. For the sake of convenience, all
+commands that require elevated priviges start with |sudo| in the following procedures.
+
+.. code-block:: bash
+
+   $ sudo percona-release enable experimental ppg-11
 
 The next steps depend on the installation package format that your operating
 system supports.
@@ -38,6 +45,11 @@ the |percona-postgresql| package is ready to be installed.
 
    $ sudo apt update
 
+.. admonition:: Platform Specific Notes
+
+   On Debian 9 (stretch), you need to `enable the llvm repository
+   <https://apt.llvm.org/>`_
+
 Install the |percona-platform-postgresql-11| using |apt-install|.
 
 .. code-block:: bash
@@ -62,13 +74,20 @@ the |percona-postgresql| package is ready to be installed.
 
    $ sudo yum update
 
-.. important::
+.. admonition:: Platform Specific Notes
 
    If you intend to install |pdp| on |rhel| v8, disable the `postgresql` module:
 
    .. code-block:: bash
 
-      $ dnf module disable postgresql
+      $ sudo dnf module disable postgresql
+
+   On |centos| 7, you should install the `epel-release` package:
+
+   .. code-block:: bash
+
+      $ sudo yum -y install epel-release
+      $ sudo yum repolist
 
 Next, install the |percona-platform-postgresql-11| using |yum-install|.