Add scripts for a single-command Danbooru deployment.

Add a Docker Compose file that launches a minimal Danbooru instance in a
Docker container with a single command. This is suitable as a quick demo
or for personal use, not for public-facing sites.

To use it, just run `bin/danbooru`. This is a wrapper script that
installs Docker Compose then uses it to start Danbooru.

This will generate a lot of debug output and take several minutes while
it builds the Docker containers. Be patient. When it's done, you should
have an empty booru accessible at http://localhost.

config/docker/docker-compose.simple.yaml

@@ -0,0 +1,44 @@
+# A Docker Compose file that launches a minimal Danbooru instance. This is
+# suitable as a quick demo or for personal use, not for public-facing sites.
+#
+# Usage:
+#
+#     $ docker-compose -f config/docker/docker-compose.simple.yaml up
+#     $ docker-compose -f config/docker/docker-compose.simple.yaml down
+
+version: "3.7"
+services:
+  danbooru:
+    # image: evazion/danbooru
+    build:
+      context: ../..
+      dockerfile: config/docker/Dockerfile.danbooru
+    ports:
+      - "80:3000"
+    environment:
+      - RAILS_ENV=development
+      - DATABASE_URL=postgresql://danbooru@postgres/danbooru
+      - DANBOORU_CANONICAL_URL=http://localhost
+    volumes:
+      - "danbooru-images:/home/danbooru/app/public/data"
+    depends_on:
+      - postgres
+    entrypoint: ["bash", "-c", "bin/rails db:setup 2> /dev/null; bin/rails server -b 0.0.0.0"]
+    user: root
+
+  postgres:
+    # image: evazion/postgres
+    build:
+      context: .
+      dockerfile: Dockerfile.postgres
+    environment:
+      POSTGRES_USER: danbooru
+      POSTGRES_HOST_AUTH_METHOD: trust
+    volumes:
+      - "danbooru-data:/var/lib/postgresql/data"
+
+volumes:
+  danbooru-images:
+    name: danbooru-images
+  danbooru-data:
+    name: danbooru-data