stringr: include make a donation

Author: gastonstat

stringr-basics.Rmd

@@ -426,3 +426,18 @@ word(change, 2, -1)
 
 `stringr` has more functions but we'll discuss them in the chapters about 
 [regular expressions](#regex1).
+
+
+-----
+
+#### Make a donation {-}
+
+If you find this resource useful, please consider making a one-time donation in any amount. Your support really matters.
+
+<form action="https://www.paypal.com/cgi-bin/webscr" method="post" target="_top">
+<input type="hidden" name="cmd" value="_donations" />
+<input type="hidden" name="business" value="ZF6U7K5MW25W2" />
+<input type="hidden" name="currency_code" value="USD" />
+<input type="image" src="https://www.paypalobjects.com/en_US/i/btn/btn_donateCC_LG.gif" border="0" name="submit" title="PayPal - The safer, easier way to pay online!" alt="Donate with PayPal button" />
+<img alt="" border="0" src="https://www.paypal.com/en_US/i/scr/pixel.gif" width="1" height="1" />
+</form>