Add README for fixtures

fixtures/README.md

@@ -0,0 +1,17 @@
+How To Create Fixtures
+======================
+
+If you want to play with actual data, use the following scripts to create checks, pings, and compute the aggregated statistics for these test checks over the last month.
+
+    > node fixtures/populate.js
+    > node fixtures/computeStats.js
+
+Then, before using the dashboard, turn on the dummy target.
+
+    > node fixtures/dummyTarget.js
+
+It's a simple server that responds to the fixture pings with a quality of service determined by the URL. For instance, 
+
+    http://localhost:8888/90
+
+will return HTTP status 200 90% of the time, and HTTP status 500 the rest of the time.