Update README.md

README.md

@@ -73,6 +73,10 @@ Sometime you may use the data based on date/time, you can call `exponentialMovin
 
 You can across check the result with You can see more detail from [StockCharts](http://stockcharts.com/school/doku.php?id=chart_school:technical_indicators:moving_averages)
 
+## Donation
+If this project help you reduce time to develop, you can give me a cup of coffee :) 
+
+[![paypal](https://www.paypalobjects.com/en_US/i/btn/btn_donateCC_LG.gif)](https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=A8YE92K9QM7NA)
 ## Note
 
  - Thank you for knowledge from [StockCharts](http://stockcharts.com/school/doku.php?id=chart_school) and [Investopedia](http://www.investopedia.com/university/stocks/). You can see more detail from their webside.