Strangler pattern FTW, well that and never have two systems share the same database. Always have one source of truth.
A great pattern is to enforce consistency in your database. Rather than e.g. adhoc code in an ORM.
And this is my diary work.
PD: I have a friend that lives on a worse situation, where they have an application based on Java 1.5 applets, with bad or not existent documentation, and nobody knows how works internally.
>The strangler pattern is a software architecture pattern where a legacy system or feature is strangled with new code.
>Make something new that obsoletes a small percentage of something old. Put them live together. Rinse and repeat.
Strangler Applications http://paulhammant.com/2013/07/14/legacy-application-strangu...