chore: import upstream snapshot with attribution

code/ch09/1st_flask_app_1/app.py

@@ -0,0 +1,10 @@
+from flask import Flask, render_template
+
+app = Flask(__name__)
+
+@app.route('/')
+def index():
+    return render_template('first_app.html')
+
+if __name__ == '__main__':
+    app.run(debug=True)