Set postage for all existing templates to service default

migrations/versions/0253_set_template_postage_.py

@@ -0,0 +1,28 @@
+"""
+
+Revision ID: 0253_set_template_postage
+Revises: 0252_letter_branding_table
+Create Date: 2019-01-30 16:47:08.599448
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = '0253_set_template_postage'
+down_revision = '0252_letter_branding_table'
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.execute(
+        """UPDATE templates SET postage = services.postage
+        FROM services WHERE template_type = 'letter' AND service_id = services.id"""
+    )
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.execute("UPDATE templates SET postage = null WHERE template_type = 'letter'")
+    # ### end Alembic commands ###