Update CONTRIBUTING.md

Author: superstructor

CONTRIBUTING.md

@@ -14,33 +14,19 @@ the [ClojureScript mailing list](https://groups.google.com/forum/#!forum/clojure
 
 ## Running tests
 
-#### Via Browser/HTML
+To run the tests, you must have recent versions of node, npm and Leiningen.
 
-To build the tests and run them in one step, just:
+To build the tests and run them in one step via karma, just:
 ```sh
-lein test-once  # compiles & then opens test.html in the browser
+npm install -g karma-cli
+lein ci 
 ```
 
 You can also get auto compiles via:
 ```sh
-lein test-auto
-```
-but you'll need to manually open `test/test.html` in a browser. And you'll also need to 
-manually reload this page after each auto compile.
-
-#### Via Karma
-
-To run the tests, you must have recent versions of node, npm, Leiningen, and a C++ compiler 
-toolchain installed. If you're on Linux or Mac OS X then you will be fine, 
-if you're on Windows then you need to install Visual Studio Community Edition, 
-and the C++ compiler dependencies.
-
-```sh
-npm install karma-cli -g # Install the Karma CLI runner
-lein deps       # runs lein-npm, installs Karma & other node dependencies. Only needed the first time.
-lein karma-once # to build re-frame tests
-karma start     # to run the tests with an auto watcher
+lein watch
 ```
+then open [http://localhost:3449/](http://localhost:3449/) in a browser for an auto-reloaded browser-based test runner.
 
 ## Pull requests for bugs