Support expansion of variables

[vguna]

Hi.

Great plugin you've written there :)!

I'm using the Multibranch plugin to automatically build features branches with Jenkins. Using your
plugin allows me to create a database per feature branch - which is really nice.

But I'm afraid of name clashes, since the database name is just suffixed with the build number. Is it possible to support variable expansion for the database name form field? So I could use ${BRANCH_NAME} from the Multibranch plugin.

Thanks!