Adding custom deployment description

Author: lostintangent

README.md

@@ -572,12 +572,24 @@ codePush.sync({ deploymentKey: userProfile.CODEPUSH_KEY });
 
 With that change in place, now it's just a matter of choosing how your app determines the right deployment key for the current user. In practice, there are typically two solutions for this:
 
-1. Expose a user-visible mechanism for changing deployments at any time. For example, your settings page could have a toggle for enabling "beta" access. This model works well if you're not concerned with the privacy of your pre-production updates, and you have power users that may want to opt-in to earlier (and potentially buggy) updates at their own will (kind of like Chrome channels). However, this solution puts the decision in the hands of your users, which doesn't help you perform A/B tests.
+1. Expose a user-visible mechanism for changing deployments at any time. For example, your settings page could have a toggle for enabling "beta" access. This model works well if you're not concerned with the privacy of your pre-production updates, and you have power users that may want to opt-in to earlier (and potentially buggy) updates at their own will (kind of like Chrome channels). However, this solution puts the decision in the hands of your users, which doesn't help you perform A/B tests transparently.
 
-2. Annotate the server-side profile's of your users with an additional piece of metadata which indicates the deployment they should sync with. By default, your app could just use the binary-embedded key, but after a user has authenticated, your server can choose to "redirect" them to a different deployment, which allows you to incrementally place certain users or groups in different deployments as needed. You could even choose to store the server-response in local storage so that it becomes the new default. How you store the key alongside your user's profiles is entirely up to your authentication solution (e.g. Auth0, Firebase, custom DB + REST API), but is generally pretty trivial to do.
+2. Annotate the server-side profile of your users with an additional piece of metadata which indicates the deployment they should sync with. By default, your app could just use the binary-embedded key, but after a user has authenticated, your server can choose to "redirect" them to a different deployment, which allows you to incrementally place certain users or groups in different deployments as needed. You could even choose to store the server-response in local storage so that it becomes the new default. How you store the key alongside your user's profiles is entirely up to your authentication solution (e.g. Auth0, Firebase, custom DB + REST API), but is generally pretty trivial to do.
 
 *NOTE: If needed, you could also implement a hybrid solution that allowed your end-users to toggle between different deployments, while also allowing your server to override that decision. This way, you have a hierarchy of "deployment resolution" that ensures your app has the ability to update itself out-of-the-box, your end users can feel rewarded by getting early access to bits, but you also have the ability to run A/B tests on your users as needed.*
 
+Since we recommend using the `Staging` deployment for pre-release testing of your updates (as explained in the previous section), it doesn't neccessarily make sense to use it for performing A/B tests on your users, as opposed to allowing early-access (as explained in option #1 above). Therefore, we recommend making full use of custom app deployments, so that you can segment your users however makes sense for your needs. For example, you could create long-term or even one-off deployments, release a variant of your app to it, and then place certain users into it in order to see how they engage.
+
+```javascript
+// #1) Create your new deployment to hold releases of a specific app variant
+code-push deployment add [APP_NAME] test-variant-one
+
+// #2) Target any new releases at that custom deployment
+code-push release-react [APP_NAME] ios -d test-variant-one
+```
+
+*NOTE: The total user count that is reported in your deployment's "Install Metrics" will take into account users that have "switched" from one deployment to another. For example, if your `Production` deployment currently reports having 1 total user, but you dynamically switch that user to `Staging`, then the `Production` deployment would report 0 total users, while `Staging` would report 1 (the user that just switched). This behavior allows you to accurately track your release adoption, even in the event of using a runtime-based deployment redirection solution.*
+
 ---
 
 ## API Reference