added a CONTRIBUTING.md, but will anybody read it?

Author: ryanflorence

.gitignore

@@ -1,3 +1,4 @@
+examples/_*
 examples/build
 node_modules
 

CONTRIBUTING.md

@@ -0,0 +1,21 @@
+### Commit subjects
+
+If your patch changes the API or fixes a bug please use one of the
+following prefixes in your commit subject:
+
+- `[fixed] ...`
+- `[changed] ...`
+- `[added] ...`
+- `[removed] ...`
+
+When releasing, a changelog is created automatically, from these
+commits.
+
+### Development
+
+- `script/test` will fire up a karma runner and watch for changes in the
+  specs directory.
+- `npm test` will do the same but doesn't watch, just runs the tests.
+- `script/build-examples` does exactly that.
+- `script/build-examples --watch` is a little more useful.
+