Initial commit: Flask calorie counter app setup

Add base Flask application with user authentication, SQLAlchemy models for users, units, and food items, admin blueprint, and basic templates. Includes database migration setup, login form, and seed script for initial user creation.

seed.py

@@ -0,0 +1,7 @@
+from application import db, app
+from models import User
+
+with app.app_context():
+    User.query.delete()
+    db.session.add(User("admin", "admin"))
+    db.session.commit()