Add information about where docs go (#55)

* Add information about where docs go

* add samples too

CONTRIBUTING.md

@@ -30,6 +30,20 @@ see a documentation issue, submit an issue using the following steps:
 Note that code issues should be filed against the individual Knative repositories,
 while documentation issues should go in the `docs` repository.
 
+### Put your docs in the right place
+
+Knative uses the [docs repository](https://github.com/knative/docs) for all
+general documentation for Knative components. However, formal specifications
+or documentation most relevant to contributors of a component should be placed
+in the `docs` folder within a given component's repository. An example of this
+is the [spec](https://github.com/knative/serving/tree/master/docs/spec)
+folder within the Serving component.
+
+Code samples follow a similar strategy, where most code samples should be located
+in the `docs` repository. If there are code examples or samples used for testing
+that are not expected to be used by non-contributors, those samples can be put
+in a `samples` folder within the component repo.
+
 ### Submitting Documentation Pull Requests
 
 If you're fixing an issue in the existing documentation, you should submit a

serving/samples/helloworld-nodejs/service.yaml

@@ -9,7 +9,7 @@ spec:
       revisionTemplate:
         spec:
           container:
-            image: docker.io/{username}/helloworld-nodejs
+            image: gcr.io/knative-samples/helloworld-nodejs
             env:
             - name: TARGET
               value: "Node.js Sample v1"