Add installing cmake to 7.2 update docs

doc/update/6.0-to-7.2.md

@@ -54,6 +54,9 @@ sudo -u git -H git checkout 7-2-stable-ee
 ```bash
 # Add support for lograte for better log file handling
 sudo apt-get install logrotate
+
+# Install cmake, which is needed for the latest versions of rugged
+sudo apt-get install cmake
 ```
 
 ## 4. Update gitlab-shell

doc/update/7.1-to-7.2.md

@@ -49,7 +49,16 @@ sudo -u git -H git fetch
 sudo -u git -H git checkout v1.9.7
 ```
 
-### 4. Install libs, migrations, etc.
+### 4. Install new system dependencies
+
+The latest version of the 'rugged' gem requires cmake to build its native
+extensions.
+
+```bash
+sudo apt-get install cmake
+```
+
+### 5. Install libs, migrations, etc.
 
 ```bash
 cd /home/git/gitlab
@@ -71,7 +80,7 @@ sudo cp lib/support/init.d/gitlab /etc/init.d/gitlab
 sudo chmod +x /etc/init.d/gitlab
 ```
 
-### 5. Update config files
+### 6. Update config files
 
 #### New configuration options for gitlab.yml
 
@@ -81,12 +90,12 @@ There are new configuration options available for gitlab.yml. View them with the
 git diff 7-1-stable:config/gitlab.yml.example 7-2-stable:config/gitlab.yml.example
 ```
 
-### 6. Start application
+### 7. Start application
 
     sudo service gitlab start
     sudo service nginx restart
 
-### 7. Check application status
+### 8. Check application status
 
 Check if GitLab and its environment are configured correctly:
 
@@ -98,7 +107,7 @@ To make sure you didn't miss anything run a more thorough check with:
 
 If all items are green, then congratulations upgrade is complete!
 
-### 8. Update OmniAuth configuration
+### 9. Update OmniAuth configuration
 
 When using Google omniauth login, changes of the Google account required.
 Ensure that `Contacts API` and the `Google+ API` are enabled in the [Google Developers Console](https://console.developers.google.com/).