Create improved Dockerfile with volume mounts for storing data

* Add volume mounts to Dockerfile to enable persisten storing of
  database and tokens when using docker
* Makefile helps with cleanup and building the Dockerfile
* Startup fires the predictify runtime inside the container
* `.dockerignore` contains files that are not needed by the docker,
  e.g. files that would otherwise slow build process down

docker/startup.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+#
+# Startup predictify. Don't use this. This is for docker specifically.
+source .venv/bin/activate
+.venv/bin/python src/runtime.py