Update README to include Docker compose directions. Fix docker-entry.sh not being executable. Update Dockerfile to fix opting-bin install issue on arm64

Dockerfile

@@ -12,4 +12,7 @@ ENV PATH /app/node_modules/.bin:$PATH
 # install and cache app dependencies
 COPY package.json /app/package.json
 
+# https://github.com/imagemin/optipng-bin/issues/97
+ENV CPPFLAGS="-DPNG_ARM_NEON_OPT=0"
+
 ENTRYPOINT ["/app/docker-entry.sh"]

README.md

@@ -34,6 +34,13 @@ Fill out `.env.sample` and save it as `.env`.
 
 `npm start` to run the production server at port 3001 (or a specified PORT).
 
+### Using Docker
+
+```bash
+$ docker compose create
+$ docker compose up
+```
+
 ## Developer notes
 
 We use [Husky](https://github.com/typicode/husky) to manage Git hooks.