add article - how to install git

doc/articles/how_to_install_git/index.md

+# Installing Git
+
+> **Article [Type](../../development/writing_documentation.html#types-of-technical-articles):** user guide ||
+> **Level:** beginner ||
+> **Author:** [Sean Packham](https://gitlab.com/SeanPackham) ||
+> **Publication date:** 2017/05/15
+
+To begin contributing to GitLab projects
+you will need to install the Git client on your computer.
+This article will show you how to install Git on macOS, Ubuntu Linux and Windows.
+
+## Install Git on macOS using the Homebrew package manager
+
+Although it is easy to use the version of Git shipped with macOS
+or install the latest version of Git on macOS by downloading it from the project website,
+we recommend installing it via Homebrew to get access to
+an extensive selection of dependancy managed libraries and applications.
+
+If you are sure you don't need access to any additional development libraries
+or don't have approximately 15gb of available disk space for Xcode and Homebrew
+use one of the the aforementioned methods.
+
+### Installing Xcode
+
+Xcode is needed by Homebrew to build dependencies.
+You can install [XCode](https://developer.apple.com/xcode/)
+through the macOS App Store.
+
+### Installing Homebrew
+
+Once Xcode is installed browse to the [Homebrew website](http://brew.sh/index.html)
+for the official Homebrew installation instructions.
+
+### Installing Git via Homebrew
+
+With Homebrew installed you are now ready to install Git.
+Open a Terminal and enter in the following command:
+
+```bash
+brew install git
+```
+
+Congratulations you should now have Git installed via Homebrew.
+Next read our article on [adding an SSH key to GitLab](../ssh/README.md).
+
+## Install Git on Ubuntu Linux
+
+On Ubuntu and other Linux operating systems
+it is recommended to use the built in package manager to install Git.
+
+Open a Terminal and enter in the following commands
+to install the latest Git from the official Git maintained package archives:
+
+```bash
+sudo apt-add-repository ppa:git-core/ppa
+sudo apt-get update
+sudo apt-get install git
+```
+
+Congratulations you should now have Git installed via the Ubuntu package manager.
+Next read our article on [adding an SSH key to GitLab](../../ssh/README.md).
+
+## Installing Git on Windows from the Git website
+
+Browse to the [Git website](https://git-scm.com/) and download and install Git for Windows.
+Next read our article on [adding an SSH key to GitLab](../../ssh/README.md).

doc/articles/index.md

@@ -12,6 +12,10 @@ They are written by members of the GitLab Team and by
 - **LDAP**
   - [How to configure LDAP with GitLab CE](how_to_configure_ldap_gitlab_ce/index.md)
 
+## Git
+
+- [How to install Git](how_to_install_git/index.md)
+
 ## GitLab Pages
 
 - **GitLab Pages from A to Z**

doc/topics/git/index.md

@@ -22,6 +22,7 @@ We've gathered some resources to help you to get the best from Git with GitLab.
   - [Cherry-picking a commit](../../user/project/merge_requests/cherry_pick_changes.md#cherry-picking-a-commit)
   - [Squashing commits](../../workflow/gitlab_flow.md#squashing-commits-with-rebase)
 - **Articles:**
+  - [How to install Git](../../articles/how_to_install_git/index.md)
   - [Git Tips & Tricks](https://about.gitlab.com/2016/12/08/git-tips-and-tricks/)
   - [Eight Tips to help you work better with Git](https://about.gitlab.com/2015/02/19/8-tips-to-help-you-work-better-with-git/)
 - **Presentations:**