Base on alpine:edge to get DNS fixes

Fix fromofficial phpMyAdmin: 6dd6b90902

See https://twitter.com/thockin/status/704909611279781888 and
gliderlabs/docker-alpine#8. This will be fixed
in 3.4, so at that point we can switch back to using stable.

Fixes #23 (DNS issues)
Fixes #27 (Kubernetes support)

mysql-backup-s3/Dockerfile

@@ -1,4 +1,4 @@
-FROM alpine:3.1
+FROM alpine:edge
 MAINTAINER Johannes Schickling "schickling.j@gmail.com"
 
 ADD install.sh install.sh