add migration to include 'opmerking' column in assessments table

backend/migrations/versions/0002_assessment_opmerking.py

@@ -0,0 +1,23 @@
+"""assessment: voeg opmerking kolom toe
+
+Revision ID: 0002
+Revises: 0001
+Create Date: 2026-03-02
+"""
+from alembic import op
+import sqlalchemy as sa
+
+revision = '0002'
+down_revision = '0001'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.add_column('assessments',
+        sa.Column('opmerking', sa.String(500), nullable=True)
+    )
+
+
+def downgrade():
+    op.drop_column('assessments', 'opmerking')