add privacy policy file

Author: adam-p

PRIVACY.md

@@ -0,0 +1,8 @@
+# Privacy Policy
+
+The _Markdown Here_ browser extension strictly does one thing: Allows users to convert Markdown to HTML inside a rich edit control. Not one thing else.
+
+This means that:
+- It collects no user or usage data.
+- It does not read or modify any part of any site besides the contents of the focused edit control, and only when the user tells it to do so.
+- It makes no external requests at all. All rendering is done locally.