Amazon S3 + Docker - "403 Forbidden: The difference between the request time and the current time is too large"

I am trying to run my django application in a docker container with static files served from Amazon S3. When I run RUN $(which python3.4) /home/docker/code/vitru/manage.py collectstatic --noinput in my Dockerfile, I get a 403 Forbidden error from Amazon S3 with the following response XML

<?xml version="1.0" encoding="UTF-8"?>
<Error>
    <Code>RequestTimeTooSkewed</Code>
    <Message>The difference between the request time and the current time is too large.</Message>
    <RequestTime>Sat, 27 Dec 2014 11:47:05 GMT</RequestTime>
    <ServerTime>2014-12-28T08:45:09Z</ServerTime>
    <MaxAllowedSkewMilliseconds>900000</MaxAllowedSkewMilliseconds>
    <RequestId>4189D5DAF2FA6649</RequestId>
    <HostId>lBAhbNfeV4C7lHdjLwcTpVVH2snd/BW18hsZEQFkxqfgrmdD5pgAJJbAP6ULArRo</HostId>
</Error>

My docker container is running Ubuntu 14.04... if that makes any difference. I also am running the application using uWSGI, without nginx or apache or any other kind of reverse-proxy server.

Attempted Solution

Other stackoverflow questions have reported a similar error using S3 (none specifically in conjunction with Docker) and they have said that this error is caused when your system clock is out of sync, and can be fixed by running

sudo service ntp stop
sudo ntpd -gq
sudo service ntp start

so I added the following to my Dockerfile, but it didn't fix the problem.

RUN apt-get install -y ntp
RUN ntpd -gq
RUN service ntp start