新增已经换源的ubuntu python3的镜像

python3-ubuntu/Dockerfile

+FROM ubuntu:16.04
+
+ENV LANG C.UTF-8
+
+RUN sed -i s@/archive.ubuntu.com/@/mirrors.aliyun.com/@g /etc/apt/sources.list \
+	&& apt-get clean \
+	&& apt-get update
+
+RUN apt-get install python3 -y \
+	&& apt-get install python3-pip -y \
+	&& mkdir -p /root/.pip \
+	&& echo '[global]\nindex_url = https://pypi.doubanio.com/simple' > /root/.pip/pip.conf \
+	&& ln -sf /usr/bin/pip3 /usr/bin/pip \
+	&& pip install --upgrade --no-cache-dir pip