Add documentation about SNAPSHOT builds

Author: samtstern

README.md

@@ -16,6 +16,7 @@ A compatible FirebaseUI client is also available for [iOS](https://github.com/fi
    1. [Compatability](#compatibility-with-firebase--google-play-services-libraries)
    1. [Upgrading dependencies](#upgrading-dependencies)
 1. [Sample App](#sample-app)
+1. [Snapshot Builds](#snapshot-builds)
 1. [Contributing](#contributing)
    1. [Installing](#installing-locally)
    1. [Deploying](#deployment)
@@ -199,6 +200,32 @@ and Gradle while trying to run the sample app, try disabling the Instant
 Run feature of Android Studio. Alternatively, update Android Studio and
 Gradle to their latest versions.
 
+## Snapshot builds
+
+Like to live on the cutting edge?  Want to try the next release of FirebaseUI before anyone else? As of version `3.2.2`
+FirebaseUI hosts "snapshot" builds on oss.jfrog.org.
+
+Just add the following to your `build.gradle`:
+
+```groovy
+repositories {
+  maven { url "https://oss.jfrog.org/artifactory/oss-release-local" }
+}
+```
+
+Then you can depend on snapshot versions:
+
+```groovy
+implementation 'com.firebaseui:firebase-ui-auth:3.2.2-SNAPSHOT`
+```
+
+You can see which `SNAPSHOT` builds are avaiable here:
+https://oss.jfrog.org/webapp/#/artifacts/browse/tree/General/oss-snapshot-local/com/firebaseui
+
+Snapshot builds come with absolutely no guarantees and we will close any issues asking to troubleshoot
+a snapshot report unless they identify a bug that should block the release launch. Experiment
+at your own risk!
+
 ## Contributing
 
 ### Installing locally