feature: docker development environment (#544)

Add docker support

It's self-contained so should not interfere with anything else and can easily be thrown out if nobody wants it anymore.

.docker/Dockerfile

@@ -0,0 +1,17 @@
+FROM ubuntu:18.04
+
+ENV LANG=en_US.utf-8 LC_ALL=en_US.utf-8 DEBIAN_FRONTEND=noninteractive
+RUN apt-get -y update
+
+COPY ./ /nyaa/
+RUN cat /nyaa/config.example.py /nyaa/.docker/nyaa-config-partial.py > /nyaa/config.py
+
+# Requirements for running the Flask app
+RUN apt-get -y install build-essential git python3 python3-pip libmysqlclient-dev curl
+# Helpful stuff for the docker entrypoint.sh script
+RUN apt-get -y install mariadb-client netcat
+
+WORKDIR /nyaa
+RUN pip3 install -r requirements.txt
+
+CMD ["/nyaa/.docker/entrypoint.sh"]