Move db.create_all() after model definitions

app.py

@@ -12,9 +12,6 @@ if not os.path.exists(UPLOAD_FOLDER):
     os.makedirs(UPLOAD_FOLDER)
 db = SQLAlchemy(app)
 
-with app.app_context():
-    db.create_all()
-
 class Subject(db.Model):
     id = db.Column(db.Integer, primary_key=True)
     name = db.Column(db.String(100), nullable=False)
@@ -269,6 +266,10 @@ def add_sample_data():
         Article(title="Lois de Newton", content="<p>La première loi de Newton...</p>", category=mechanics)
         db.session.commit()
 
+with app.app_context():
+    db.create_all()
+    add_sample_data()
+
 
 # Helper to convert a standard YouTube URL into an embeddable URL
 from urllib.parse import urlparse, parse_qs