Add tooltip for #398
Add tooltip for #398

Also to assist with #398, add a tooltip instructing what to do to add a tag, to the list of tags.
mpurzynski/MozDef,gdestuynder/MozDef,jeffbryner/MozDef,gdestuynder/MozDef,Phrozyn/MozDef,gdestuynder/MozDef,mpurzynski/MozDef,jeffbryner/MozDef,mozilla/MozDef,Phrozyn/MozDef,gdestuynder/MozDef,mozilla/MozDef,jeffbryner/MozDef,mozilla/MozDef,Phrozyn/MozDef,Phrozyn/MozDef,mpurzynski/MozDef,mozilla/MozDef,jeffbryner/MozDef,mpurzynski/MozDef