build(app): Fix deploy commands

app.py

@@ -1,10 +1,12 @@
+import os
 import subprocess
 
 subprocess.run("echo 'node version:' && node --version", shell=True)
 subprocess.run("echo 'npm version:' && npm --version", shell=True)
 subprocess.run("pwd && ls -al", shell=True)
-subprocess.run("export PORT=7860", shell=True)
-subprocess.run(["echo", '"PORT set to \$PORT"'])
+
+subprocess.run("export PORT='7860'", shell=True)
+print(f'PORT set to {os.getenv("PORT")}')
 
 subprocess.run("npm --prefix app install", shell=True)
 subprocess.run("npm run build --prefix app", shell=True)