Port to v10

document_knowledge/models/ir_attachment.py

@@ -0,0 +1,8 @@
+from odoo import fields, models
+
+
+class IrAttachment(models.Model):
+    _inherit = 'ir.attachment'
+
+    # Add index to res_model because filtering on it is a common use case
+    res_model = fields.Char(index=True)