diff --git a/backend/alembic/versions/015_modify_chat.py b/backend/alembic/versions/015_modify_chat.py
new file mode 100644
index 0000000..c1c961f
--- /dev/null
+++ b/backend/alembic/versions/015_modify_chat.py
@@ -0,0 +1,33 @@
+"""015_modify_chat
+
+Revision ID: 02d84523a979
+Revises: fde8acca6143
+Create Date: 2025-06-25 15:45:14.968598
+
+"""
+from alembic import op
+import sqlalchemy as sa
+import sqlmodel.sql.sqltypes
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision = '02d84523a979'
+down_revision = 'fde8acca6143'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.alter_column('chat', 'datasource',
+               existing_type=sa.INTEGER(),
+               nullable=True)
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.alter_column('chat', 'datasource',
+               existing_type=sa.INTEGER(),
+               nullable=False)
+    # ### end Alembic commands ###