Add migrations directory on generation of example-product
Add migrations directory on generation of example-product

 -Migrations directory is now required by Ops Manager

Signed-off-by: Andrew Cantino <30a5a5ed182f2be1f5c66c301077821aad8b5d90@pivotal.io>

pivotal-cf-experimental/ops-manager-example,pivotal-cf-experimental/ops-manager-example,pivotal-cf-experimental/ops-manager-example,pivotal-cf-experimental/ops-manager-example