Enhance Article editor

app/models.py

@@ -262,3 +262,27 @@ class KnowledgeBase(db.Model):
 
     def __repr__(self):
         return f'<KnowledgeBase {self.title}>'
+
+
+class KBAttachment(db.Model):
+    """Files and images attached to a Knowledge Base article."""
+    __tablename__ = 'kb_attachments'
+
+    id          = db.Column(db.Integer, primary_key=True)
+    article_id  = db.Column(db.Integer, db.ForeignKey('knowledge_base.id'), nullable=False)
+    filename    = db.Column(db.String(256), nullable=False)   # original name
+    stored_name = db.Column(db.String(256), nullable=False)   # UUID-based on disk
+    mime_type   = db.Column(db.String(100))
+    file_size   = db.Column(db.Integer)
+    uploaded_by = db.Column(db.Integer, db.ForeignKey('users.id'))
+    uploaded_at = db.Column(db.DateTime, default=datetime.utcnow)
+
+    article     = db.relationship('KnowledgeBase', backref=db.backref('attachments', lazy='dynamic', cascade='all, delete-orphan'))
+    uploader    = db.relationship('User', foreign_keys=[uploaded_by])
+
+    @property
+    def url(self):
+        return f'/admin/kb/files/{self.stored_name}'
+
+    def __repr__(self):
+        return f'<KBAttachment {self.filename}>'