feat: add environment variable handling in Dockerfile and update Firebase configuration

env.sh

@@ -0,0 +1,12 @@
+#!/bin/sh
+for i in $(env | grep MY_APP_)
+do
+    key=$(echo $i | cut -d '=' -f 1)
+    value=$(echo $i | cut -d '=' -f 2-)
+    echo $key=$value
+    # sed All files
+    # find /usr/share/nginx/html -type f -exec sed -i "s|${key}|${value}|g" '{}' +
+
+    # sed JS and CSS only
+    find /usr/share/nginx/html -type f \( -name '*.js' -o -name '*.css' \) -exec sed -i "s|${key}|${value}|g" '{}' +
+done