package: add "contributors" section

TooTallNate · TooTallNate · commit a4de5389c0a5 · 2014-06-05T00:36:36.000-07:00
Feel free to add yourself in a PR if you've contributed a patch
in the past.
diff --git a/package.json b/package.json
@@ -12,6 +12,9 @@
     "debugger"
   ],
   "author": "TJ Holowaychuk <tj@vision-media.ca>",
+  "contributors": [
+    "Nathan Rajlich <nathan@tootallnate.net> (http://n8.io)"
+  ],
   "dependencies": {
     "ms": "0.6.2"
   },
