added Docker setup & moved database into instance folder

webapp/__init__.py

@@ -1,4 +1,5 @@
 from __future__ import annotations
+import os
 from flask import Flask, render_template
 from datetime import datetime
 
@@ -26,6 +27,12 @@ def create_app() -> Flask:
             return str(value)
     app.jinja_env.filters["fmt_ts"] = fmt_ts
 
+    # ensure the instance folder exists
+    try:
+        os.makedirs(app.instance_path)
+    except OSError:
+        pass
+
     # Blueprints registrieren
     app.register_blueprint(structures_bp)
     app.register_blueprint(cookbook_bp)