Update README.md

README.md

@@ -16,6 +16,10 @@ The bitwarden Web project is an AngularJS application that powers the web vault
 Unless you are running the [Core](https://github.com/bitwarden/core) API locally, you'll probably need to switch the 
 application to target the production API. Open `package.json` and set `production` to `true`.
 
+By default the application points to the production API. If you want to change that to point to a local instance of
+the [Core](https://github.com/bitwarden/core) API, you can modify the `package.json` `env` property to `Development`
+and then set your local endpoints in `settings.json`.
+
 Then run the following commands:
 
 - `npm install`