removing hostname from config, re: [change to persona audience setup](https://groups.google.com/forum/#dev/XGJeGGtRtgo)
Revert "removing hostname from config, re: [change to persona audience setup](https://groups.google.com/forum/#dev/XGJeGGtRtgo)"

This reverts commit 92edd8b32505c4c3c993202cdecbeecfae646ff6.
keeping hostname in config, but changing the explanation
upgrading version of badge-bakery
Merge pull request #941 from cmcavoy/development

Update README / config to remove hostname as setting.