added bower installation guide to the read me file

README.md

@@ -1,3 +1,4 @@
+## Sass flexbox mixin
 This is a set of mixins for those who want to mess
 around with flexbox using the native support of current
 browsers. For full support table check: http://caniuse.com/flexbox
@@ -7,6 +8,11 @@ Basically this will use:
 - Prefixed standard syntax (Chrome)
 - Final standards syntax (FF, IE11, Opera 12.1)
 
+## Installation
+#### Bower
+
+`bower install sass-flex-mixin`
+
 ------------------------
 This was inspired by: 
 - http://dev.opera.com/articles/view/advanced-cross-browser-flexbox/
@@ -18,4 +24,4 @@ With help from:
 
 A version compatible with Compass is provided by @trinonsense, on the compass branch.
 
-Licensed under MIT.
+Licensed under MIT.