Add markdown format support (#25)

Co-authored-by: Dawid Dziurla <dawidd0811@gmail.com>

node_modules/showdown/DONATIONS.md

@@ -0,0 +1,57 @@
+We would like to thank everyone that contributed to this library. If you find our library useful and wish to donate as well, you can do so [through patreon](https://www.patreon.com/showdownjs) or directly [through paypal](https://www.paypal.me/tiviesantos)!! Your contribution will be greatly appreciated.
+
+# Sponsors
+
+## Platinum Supporters
+
+## Gold Supporters
+
+## Silver Supporters
+
+
+# Patron Supporters
+
+## Awesome Supporter
+
+## Cool Supporter
+
+## Supporter
+
+ - Ricardo Jordão
+ 
+ - Tiago Silva
+
+
+---
+
+# One Time Donors
+
+- [**Learn on demand Systems**](http://www.learnondemandsystems.com/) (1000$)
+
+- **Nothing AG** (25€)
+
+    > Thank you for developing Showdown :)
+
+- **Sam Huffman** (15$)
+
+    > Thanks for the great work on showdown.js! I've been looking for a good solution to serve wiki-like text to a browser and render as
+    HTML but nearly gave up after mixed success with wikitext. Your library gets me very close to where I want to be.
+
+- **Maya Lekova** (10$)
+
+    > Great work with the showdown library! I just used it and it worked exactly the way I expected 
+      (given a complex inline HTML inside the Markdown, which renders fine with other viewers). 
+      The other libraries I've tried (markdown-it and marked) produced a lot of bogus output. Y
+      our library saved me at least half a day, thanks! Good luck :)
+
+- **Lin Wang** (10$)
+
+- **Walter Schnell** (10$)
+
+- **ivanhjc** (5$)
+
+- **Asbjørn Ulsberg** (5$)
+
+    > Thanks for the ShowdownJS support!
+
+- **Juan Marcelo Russo** (1$)