Add robots file and sitemap.xml (#5)

* Create robots.txt

* Create sitemap.xml

Author: keenhenry

robots.txt

@@ -0,0 +1,9 @@
+# Dear Robot, be nice!
+
+User-agent: * 
+
+Disallow: /assets/img/
+
+Sitemap: https://keenhenry.github.io/sitemap.xml
+
+# PEACE