Update Dockerfile to support building on Docker Cloud

Dockerfile

@@ -1,14 +1,22 @@
 FROM node:7.2.1-alpine
 
-# Copy application files
-COPY ./build /usr/src/app
-WORKDIR /usr/src/app
-
 ENV DATABASE_PATH db/wedding.db
 ENV PORT 80
-
 EXPOSE 80
 
+# Install additional dependencies
+RUN apk add --no-cache make gcc g++ python
+
+# Copy app
+COPY ./ /usr/src/app
+WORKDIR /usr/src/app
+
+# Install dev dependencies and build release
+RUN npm install --silent
+RUN npm run build --release --silent
+
+WORKDIR /usr/src/app/build
+
 # Install Node.js dependencies
 RUN npm install --production --silent