add version to docs

docs/DOCS_README.md

@@ -20,7 +20,8 @@ a private website repository has make targets consumed by a standard Jenkins tas
 ## README
 
 The [README.md](./README.md) is also the landing page for the documentation
-on the website.
+on the website. During the Jenkins build, the current commit is added to the bottom
+of the README.
 
 ## Config.js
 

docs/README.md

@@ -39,3 +39,7 @@ Dive deep into the spec. There's one for each Tendermint and the ABCI
 
 See [this file](./DOCS_README.md) for details of the build process and
 considerations when making changes.
+
+## Version
+
+This documentation is built from the following commit: