Merge pull request #550 from phuu/patch-1

Add note about overwriting git aliases

Author: hemanth

Installation.md

@@ -27,6 +27,8 @@ $ sudo apt-get install git-extras
 $ brew install git-extras
 ```
 
+Installing from Homebrow will not give you the option omit certain `git-extras` if they conflict with existing git aliases. To have this option, build from source.
+
 ### Windows
 
 First, please install `Git for Windows 2.x` from 'https://github.com/git-for-windows/git/releases'.