xcode 6 in el capitan beta 2

1. Open this file /System/Library/CoreServices/CoreTypes.bundle/Contents/Resources/Exception.plist
2. Find lines with name xcode in them (http://i.imgur.com/tcKWLhz.png)
3. Edit value HardDisabled from YES to NO
4. Save and reboot

1a If you can't save because file says it's locked then enable rootless mode (sudo nvram boot-args="kext-dev-mode=1 rootless 0" or sudo nvram boot-args="kext-dev-mode=1 rootless=0") and reboot.
1b If you still have problem, copy Exceptions.plist to Desktop (or wherever else) and edit it them.
1c Save it and them remove Exceptions.plist in System (sudo rm -rf /System/Library/CoreServices/CoreTypes.bundle/Contents/Resources/Exceptions.plist)
1d Copy file from Desktop (or wherever else) to /System/Library/CoreServices/CoreTypes.bundle/Contents/Resources and reboot.

Happy Xcode6