Updated Home (markdown)

Home.md

@@ -1 +1,5 @@
-Welcome to the pai wiki!
+Welcome to OpenPAI WIKI! These pages are primarily intended for those who wish to contribute to the OpenPAI project by submitting bug reports, suggesting new features, building extensions, commenting on new ideas, or even by submitting pull requests.
+
+Please refer to the sidebar (on the right) for details on Project Management, Contributing to Code, and Documentation.
+
+If you are looking for more information on using OpenPAI, please visit https://github.com/Microsoft/pai home directly!