use environment variables for configuration

Dockerfile

@@ -1,8 +1,29 @@
 FROM node:12-alpine
 
-ARG REDIS_URL
-ARG DEBUG
+ARG AVATAR_MIN
+ARG AVATAR_MAX
+ARG AVATAR_DEFAULT
+ARG RENDER_MIN
+ARG RENDER_MAX
+ARG RENDER_DEFAULT
+ARG FACE_DIR
+ARG HELM_DIR
+ARG SKIN_DIR
+ARG RENDER_DIR
+ARG CAPE_DIR
+ARG CACHE_LOCAL
+ARG CACHE_BROWSER
 ARG EPHEMERAL_STORAGE
+ARG REDIS_URL
+ARG PORT
+ARG BIND
+ARG EXTERNAL_HTTP_TIMEOUT
+ARG DEBUG
+ARG LOG_TIME
+ARG SPONSOR_SIDE
+ARG TOP_RIGHT
+
+ENV NODE_ENV production
 
 RUN apk --no-cache --virtual .build-deps add git python build-base
 RUN apk --no-cache --virtual .canvas-deps add cairo-dev pango-dev jpeg-dev giflib-dev
@@ -15,8 +36,7 @@ RUN mkdir -p /crafatar/images/capes
 
 VOLUME /crafatar/images
 
-COPY package.json www.js crafatar/
-COPY config.example.js crafatar/config.js
+COPY package.json www.js config.js crafatar/
 COPY lib/ crafatar/lib/
 
 WORKDIR /crafatar