Docker config for testing python-build (#1548)

* Dockerfile for testing python builds

* README: document docker usage

* Finish docker

dockerignore file, specify ephemeral nature of containers.

* Move docs for docker usage to python-build README

Dockerfile

@@ -0,0 +1,35 @@
+FROM ubuntu:18.04
+
+LABEL maintainer="Chris L. Barnes <chrislloydbarnes@gmail.com>"
+
+ENV DEBIAN_FRONTEND=noninteractive
+
+RUN apt-get update -y \
+    && apt-get install -y \
+        make \
+        build-essential \
+        libssl-dev \
+        zlib1g-dev \
+        libbz2-dev \
+        libreadline-dev \
+        libsqlite3-dev \
+        wget \
+        curl \
+        llvm \
+        libncurses5-dev \
+        libncursesw5-dev \
+        xz-utils \
+        tk-dev \
+        libffi-dev \
+        liblzma-dev \
+        python-openssl \
+        git \
+    && rm -rf /var/lib/apt/lists/*
+
+ENV PYENV_ROOT "/pyenv"
+ENV PATH "$PYENV_ROOT/bin:$PATH"
+
+COPY . /pyenv
+
+RUN eval "$(pyenv init -)"
+