A few months ago, I came across PassBolt.

Currently at work we’re using TeamPass, but we feel
it’s not that usable.
PassBolt uses Open Source technology such as GnuPG, CakePHP, OpenSSL and other software.

Currently, the demo is rather basic as a lot of functionality is still to be built.
But even when that’s the case, the interface looks clean and fresh ; the experience smooth.
Have a look at their roadmap, and see why this really could become a gem!
https://www.passbolt.com/roadmap