ubuntu/16.04 fails to build

[alexkalderimis]

Error: /bin/sh: 1: locale-gen: not found

Build output:

$ docker build 'https://github.com/rubinius/docker.git#master:ubuntu/16.04'
Sending build context to Docker daemon   2.56kB
Step 1/13 : FROM ubuntu:16.04
16.04: Pulling from library/ubuntu
80bce60046fa: Pull complete
55a738a15540: Pull complete
e19cf0706c62: Pull complete
de4cdd6c27d1: Pull complete
Digest: sha256:98afb2808ee1ec6aa4d7c8f8b82c6347b9ae156932f7186182b997f3d5616ebe
Status: Downloaded newer image for ubuntu:16.04
 ---> 9ff95a467e45
Step 2/13 : RUN locale-gen en_US.UTF-8
 ---> Running in 888251fd6f30
/bin/sh: 1: locale-gen: not found
The command '/bin/sh -c locale-gen en_US.UTF-8' returned a non-zero code: 127