Turn on search endpoint

Need this to actually turn on search endpoint

Author: zachaller

README.md

@@ -54,6 +54,7 @@ docker run \
          -e STORAGE_PATH=/registry \
          -e AWS_KEY=myawskey \
          -e AWS_SECRET=myawssecret \
+         -e SEARCH_BACKEND=sqlalchemy \
          -p 5000:5000 \
          registry
 ```