Add stock feature documentation

README.md

@@ -6,4 +6,6 @@
 
 [Updating to a new version of OpenRC](updating)
 
+[Using the stock build variant](buildvariants)
+
 [Benchmarks](benchmarks)

buildvariants.md

@@ -0,0 +1,22 @@
+# OpenRC Stock Build Variant
+
+Beginning with version 2.0 beta 1, OpenRC projects have the ability to build a stock version of the app
+without moving any code. Modified SDKs
+[have been ruled illegal for competition use by the GDC](https://ftcforum.usfirst.org/forum/i-first-i-tech-challenge-game-q-and-a-forum-this-is-a-moderated-forum/first-relic-recovery-presented-by-qualcomm-game-q-a-forum/robot-inspection-rules/answers-electrical-materials/50465-control-system-answers?p=63242#post63242),
+but with this feature, you can easily use the features and speed of OpenRC while you develop your OpModes,
+and then quickly deploy a legal version of the app to your phone before a competition.
+
+### Note: Any modifications you make to any built-in modules other than FtcRobotController and TeamCode will NOT be applied when you are using the stock build variant.
+If you've added your own modules (e.g. for OpenCV), those are safe.
+
+## Instructions
+To switch between the "stock" and "openrc" build variants, choose `Build > Select Build Variant` from the menu.
+There's also a Build Variants tab in the lower left corner area of Android Studio  (assuming that you haven't
+collapsed the bars along the edges by clicking on the little window icon in the very bottom left corner).
+
+Choose the appropriate option from the dropdown next to the `TeamCode` module. The build variants will have
+`Debug` appended to them.
+
+When you switch to a new build variant, it's recommended to sync the project with the Gradle files. 
+For Android Studio 3.0, you can find that option under `Tools > Android`. Starting in Android Studio 3.1, that
+option is located in the `File` menu.