Container: add Webpack Encore watcher

Issue #111

container/npm/Dockerfile

@@ -0,0 +1,8 @@
+FROM node:14-alpine3.10
+
+RUN apk --no-cache add su-exec entr
+
+COPY entrypoint.sh /usr/local/bin/custom-entrypoint
+ENTRYPOINT ["custom-entrypoint"]
+
+WORKDIR /srv

container/npm/entrypoint.sh

@@ -0,0 +1,8 @@
+#!/bin/sh -e
+
+# Make it easier to run the application first time. :)
+if [[ ! -d node_modules ]]; then
+    su-exec $(stat -c '%u:%g' .) npm install
+fi
+
+echo webpack.config.js | su-exec $(stat -c '%u:%g' .) entr -r npm run watch

docker-compose.yaml

@@ -15,6 +15,11 @@ services:
         volumes:
             - '.:/srv:z'
 
+    js:
+        build: 'container/npm'
+        volumes:
+            - '.:/srv:z'
+
     db:
         image: 'mysql:5.7'
         ports: