Install Python 3.5 and 3.6 on docker container

To cover all supported versions of Python using Tox

docker/bin/entrypoint.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+set -e
+
+eval "$(pyenv init -)"
+eval "$(pyenv virtualenv-init -)"
+source /root/.pyenv/completions/pyenv.bash
+
+pip install tox
+
+exec $@
+

docker/bin/install_python.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+set -e
+
+export CFLAGS='-O2'
+export EXTRA_CFLAGS="-DTHREAD_STACK_SIZE=0x100000"
+
+curl -L https://raw.githubusercontent.com/pyenv/pyenv-installer/master/bin/pyenv-installer | bash
+eval "$(pyenv init -)"
+
+for ver in $@
+do
+    pyenv install $ver
+done
+
+pyenv global $@
+pip install --upgrade pip
+pyenv rehash