merge current master

Dockerfile

@@ -1,9 +1,10 @@
 FROM alpine:3.6
 
 RUN apk --no-cache add python py-setuptools py-pip && \
-    pip install elasticsearch-curator==5.2.0 && \
+    pip install elasticsearch-curator==5.4.0 && \
+    pip install boto3 && \
     pip install requests-aws4auth && \
-    apk del py-pip 
+    apk del py-pip
 
 USER nobody:nobody
 ENTRYPOINT ["/usr/bin/curator"]