Add info about callback in options resolver#3437

Merged

weaverryan merged 2 commits intosymfony:masterfrom

marekkalnik:feature/options-resolver-callback-support

Jan 21, 2014

Commits on Jan 6, 2014

Add info about callback in options resolver
marekkalnik
committed

Commits on Jan 13, 2014

Fix according to PR comments
marekkalnik
committed