Add migration for adding EvaluationResult.steps

migrations/versions/c9593d76dbce_add_steps_column_to_evaluation_results_.py

+"""Add steps column to evaluation_results table
+
+Revision ID: c9593d76dbce
+Revises: 83bb00cf8918
+Create Date: 2021-04-21 10:44:40.676401
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'c9593d76dbce'
+down_revision = '83bb00cf8918'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    with op.batch_alter_table('evaluation_results') as batch_op:
+        batch_op.add_column(
+            sa.Column('steps', sa.Integer(), nullable=True)
+        )
+
+
+def downgrade():
+    with op.batch_alter_table('evaluation_results') as batch_op:
+        batch_op.drop_column('steps')