My project Reshape (https://github.com/fabianlindfors/reshape https://github.com/fabianlindfors/reshape) might be interesting to you, it's a bit like blue/green

My project Reshape (https://github.com/fabianlindfors/reshape https://github.com/fabianlindfors/reshape) might be interesting to you, it's a bit like blue/green DB deployments in that it uses a two-step process where it can support both the old and the new schema at the same time during the deployment phase.