Check updates to the GitHub today, Magento 2 introduced new command to automatically generate all the URN resolutions for the PhpStorm.
To use it: have Magento installed on the same machine as PhpStorm go to the root directory execute command
$ php bin/magento dev:urn-catalog:generate .idea/misc.xml
where .idea/misc.xml
is path to your PhpStorm misc.xml
file
All of the URNs should be magically resolved now!
Check them under PhpStorm->Preferences -> Languages&Frameworks -> Schemas and DTDs
PhpStorm 9.0 (windows) : File -> Settings -> Languages&Frameworks -> Schemas and DTDs