Add a recommendation to the Guava README that libraries using Guava use the Beta Checker.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=179830005
diff --git a/README.md b/README.md
index 114fee8..bbd386d 100644
--- a/README.md
+++ b/README.md
@@ -74,7 +74,9 @@
 are subject to change. They can be modified in any way, or even
 removed, at any time. If your code is a library itself (i.e. it is
 used on the CLASSPATH of users outside your own control), you should
-not use beta APIs, unless you repackage them (e.g. using ProGuard).
+not use beta APIs, unless you repackage them (e.g. using ProGuard). **If your
+code is a library, we strongly recommend using the [Guava Beta Checker] to
+ensure that you do not use any `@Beta` APIs!**
 
 2. APIs without `@Beta` will remain binary-compatible for the indefinite
 future. (Previously, we sometimes removed such APIs after a deprecation period.
@@ -100,6 +102,7 @@
 [guava-snapshot-api-docs]: http://google.github.io/guava/releases/snapshot-jre/api/docs/
 [guava-snapshot-api-diffs]: http://google.github.io/guava/releases/snapshot-jre/api/diffs/
 [Guava Explained]: https://github.com/google/guava/wiki/Home
+[Guava Beta Checker]: https://github.com/google/guava-beta-checker
 
 <!-- References -->