docs: link to live preview. (#84)

README.md

@@ -10,14 +10,16 @@
 
 This is a framework for building checks designed to check to see if a
 repository follows guidelines. By itself, it does nothing - it requires at
-least one plugin to be installed..
+least one plugin to be installed.
 
 With one or more plugins, it will produce a list of results - green checkmarks
 mean this rule is followed, red x’s mean the rule is not. A yellow warning sign
 means that the check was skipped because a previous required check failed.
 
 `sp-repo-review` provides checks based on the
-[Scientific-Python Development Guide][] at [scientific-python/cookie][].
+[Scientific-Python Development Guide][] at [scientific-python/cookie][]. A live
+WebAssembly demo using `sp-repo-review` is
+[here](https://scientific-python.github.io/repo-review).
 
 ## Running repo-review