Update Dockerfile to use non-root user

Dockerfile

@@ -1,9 +1,15 @@
 FROM node:14-alpine
 LABEL maintainer="me@kevinthomas.dev"
+RUN deluser --remove-home node \
+  && addgroup -S noisedash -g 1440 \
+  && adduser -S -G noisedash -u 1440 noisedash
+RUN mkdir /var/noisedash
+RUN chown noisedash:noisedash /var/noisedash
+USER noisedash
 WORKDIR /var/noisedash
-COPY package*.json ./
+COPY --chown=noisedash:noisedash package*.json ./
 RUN npm install
-COPY . .
+COPY --chown=noisedash:noisedash . .
 ENV NODE_ENV production
 RUN npm run build
 EXPOSE 1432