Update contributing.md for using a local plotly.js

Author: ayjayt

contributing.md

@@ -224,7 +224,30 @@ the `plotly/plotly.js` GitHub repository (and place them in
 `plotly/package_data`). It will then regenerate all of the `graph_objs`
 classes based on the new schema.
 
-For dev branches, it is also possible to use `updateplotlyjsdev --devrepo reponame --devbranch branchname` to update to development versions of `plotly.js`. This will fetch the `plotly.js` in the CircleCI artifact of the branch `branchname` of the repo `reponame`. If `--devrepo` or `--devbranch` are omitted, `updateplotlyjsdev` defaults using `plotly/plotly.js` and `master` respectively.
+For dev branches, it is also possible to use `updateplotlyjsdev` in two configurations:
+
+### CircleCI Release
+
+If your devbranch is part of the official plotly.js repository, you can use 
+```bash
+python setup.py updateplotlyjsdev --devrepo reponame --devbranch branchname
+``` 
+to update to development versions of `plotly.js`. This will fetch the `plotly.js` in the CircleCI artifact of the branch `branchname` of the repo `reponame`. If `--devrepo` or `--devbranch` are omitted, `updateplotlyjsdev` defaults using `plotly/plotly.js` and `master` respectively.
+
+### Local Repository
+
+If you have a local repository of `plotly.js` you'd like to try, you can run:
+
+```bash
+# In your plotly.js/ directory, prepare the package:
+
+$ npm run build
+$ npm pack
+$ mv plotly.js-*.tgz plotly.js.tgz
+
+# In your plotly.py/packages/python/plotly/ directory:
+$ python setup.py updateplotlyjsdev --local /path/to/your/plotly.js/
+```
 
 ## Testing