add npm shield

XOP · XOP · commit df80ffd0effa · 2015-10-23T17:31:40.000+03:00
diff --git a/README.md b/README.md
@@ -1,5 +1,7 @@
 # postcss-rgba-hex
 
+[![npm version](https://badge.fury.io/js/postcss-rgba-hex.svg)](https://www.npmjs.com/package/postcss-rgba-hex)
+
 > [PostCSS](https://github.com/postcss/postcss) plugin that replaces RGB(a) values with hexadecimal analogues
 
 
