Add docker environment for local development (#257)

* Add docker environment

* Add document of docker

* Move docker files

* Change context

* Move git submodule command to entrypoint.sh

* Update README

docker/Dockerfile

@@ -0,0 +1,14 @@
+FROM nimlang/nim:1.2.6-ubuntu
+
+RUN apt-get update -yqq \
+    && apt-get install -y --no-install-recommends \
+               libsass-dev \
+               sqlite3 \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+COPY . /app
+
+# install dependencies
+RUN nimble install -Y

docker/docker-compose.yml

@@ -0,0 +1,12 @@
+version: "3.7"
+
+services:
+  forum:
+    build:
+      context: ../
+      dockerfile: ./docker/Dockerfile
+    volumes:
+      - "../:/app"
+    ports:
+      - "5000:5000"
+    entrypoint: "/app/docker/entrypoint.sh"

docker/entrypoint.sh

@@ -0,0 +1,19 @@
+#!/bin/sh
+
+set -eu
+
+git submodule update --init --recursive
+
+# setup
+nimble c -d:release src/setup_nimforum.nim
+./src/setup_nimforum --dev
+
+# build frontend
+nimble c -r src/buildcss
+nimble js -d:release src/frontend/forum.nim
+mkdir -p public/js
+cp src/frontend/forum.js public/js/forum.js
+
+# build backend
+nimble c src/forum.nim
+./src/forum