The OnePlus 2 is one heck of a budget flagship device. One of its main selling points is its developer friendliness. It comes preloaded with a custom rom for crying out loud! Unlocking your bootloader is super easy. All you have to do is type the unlock command "fastboot oem ulock" in a command prompt while your phone is in fastboot mode. Installing a custom recovery and rooting the phone is just as easy. Head to the link below for the full in depth tutorial on all things root for the OnePlus 2.
via XDA