Fix Redis installation guide

[ci skip]

doc/install/installation.md

@@ -182,25 +182,20 @@ We recommend using a PostgreSQL database. For MySQL check [MySQL setup guide](da
 ## 6. Redis
-As of this writing, most Debian/Ubuntu distributions ship with Redis 2.2 or
-2.4. GitLab requires at least Redis 2.8.
-Ubuntu users [can use a PPA](https://launchpad.net/~chris-lea/+archive/ubuntu/redis-server)
-to install a recent version of Redis.
-
-The following instructions cover building and installing Redis from scratch:
+GitLab requires at least Redis 2.8.
+If you are using Debian 8 or Ubuntu 14.04 and up, then you can simply install
+Redis 2.8 with:
 ```sh
-# Build Redis
-wget http://download.redis.io/releases/redis-2.8.23.tar.gz
-tar xzf redis-2.8.23.tar.gz
-cd redis-2.8.23
-make
-# Install Redis
-cd utils
-sudo ./install_server.sh
+sudo apt-get install redis-server
+```
+If you are using Debian 7 or Ubuntu 12.04, follow the special documentation
+on [an alternate Redis installation](redis.md). Once done, follow the rest of
+the guide here.
+```
 # Configure redis to use sockets
 sudo cp /etc/redis/redis.conf /etc/redis/redis.conf.orig
@@ -224,7 +219,7 @@ if [ -d /etc/tmpfiles.d ]; then
 fi
 # Activate the changes to redis.conf
-sudo service redis_6379 start
+sudo service redis-server restart
 # Add git to the redis group
 sudo usermod -aG redis git

doc/install/redis.md

+# Install Redis on old distributions
+
+GitLab requires at least Redis 2.8. The following guide is for Debian 7 and
+Ubuntu 12.04. If you are using Debian 8 or Ubuntu 14.04 and up, follow the
+[installation guide](installation.md).
+
+## Install Redis 2.8 in Debian 7
+
+Redis 2.8 is included in the Debian Wheezy [backports] repository.
+
+1. Edit `/etc/apt/sources.list` and add the following line:
+
+    ```
+    deb http://http.debian.net/debian wheezy-backports main
+    ```
+
+1. Update the repositories:
+
+    ```
+    sudo apt-get update
+    ```
+
+1. Install `redis-server`:
+
+    ```
+    sudo apt-get -t wheezy-backports install redis-server
+    ```
+
+1. Follow the rest of the [installation guide](installation.md).
+
+## Install Redis 2.8 in Ubuntu 12.04
+
+We will [use a PPA](https://launchpad.net/~chris-lea/+archive/ubuntu/redis-server)
+to install a recent version of Redis.
+
+1. Install the PPA repository:
+
+    ```
+    sudo add-apt-repository ppa:chris-lea/redis-server
+    ```
+
+    Your system will now fetch the PPA's key. This enables your Ubuntu system to
+    verify that the packages in the PPA have not been interfered with since they
+    were built.
+
+1. Update the repositories:
+
+    ```
+    sudo apt-get update
+    ```
+
+1. Install `redis-server`:
+
+    ```
+    sudo apt-get install redis-server
+    ```
+
+1. Follow the rest of the [installation guide](installation.md).
+
+[backports]: http://backports.debian.org/Instructions/ "Debian backports website"