add Dockerfile and configure production app

package.json

@@ -25,7 +25,7 @@
     "postcss-loader": "^7.3.0",
     "sass": "^1.62.1",
     "sass-loader": "^13.2.2",
-    "shakapacker": "6.6.0",
+    "shakapacker": "7.0.0",
     "signature_pad": "^4.1.5",
     "tailwindcss": "^3.3.2",
     "terser-webpack-plugin": "5.3.8",