Add workflow id column to executions_v2 table

Partially implements: blueprint use-workflow-id-in-rest-api

Change-Id: Iad7f1024576b31307016c0f1b4057c794bf4e30b

mistral/db/sqlalchemy/migration/alembic_migrations/versions/011_add_workflow_id_for_execution.py

@@ -0,0 +1,36 @@
+# Copyright 2016 OpenStack Foundation.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""add workflow id for execution
+
+Revision ID: 011
+Revises: 010
+Create Date: 2016-02-02 22:29:34.672735
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '011'
+down_revision = '010'
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade():
+    op.add_column(
+        'executions_v2',
+        sa.Column('workflow_id', sa.String(length=80), nullable=True)
+    )