Add install size badge & reasons why Cashify was created

readme.md

@@ -2,7 +2,14 @@
 
 > Lightweight currency conversion library, successor of money.js
 
-[![Build Status](https://travis-ci.org/xxczaki/cashify.svg?branch=master)](https://travis-ci.org/xxczaki/cashify) [![XO code style](https://img.shields.io/badge/code_style-XO-5ed9c7.svg)](https://github.com/xojs/xo)
+[![Build Status](https://travis-ci.org/xxczaki/cashify.svg?branch=master)](https://travis-ci.org/xxczaki/cashify) [![XO code style](https://img.shields.io/badge/code_style-XO-5ed9c7.svg)](https://github.com/xojs/xo) [![install size](https://packagephobia.now.sh/badge?p=cashify)](https://packagephobia.now.sh/result?p=cashify)
+
+This package was created, because the popular [money.js]() library is:
+* not maintained (last commit was ~5 years ago)
+* has over 20 issues open
+* does not support TypeScript
+* has implicit globals
+* does not have any unit tests
 
 ## Highlights