STALLED
This project is no longer maintained because its promises and API are not up to standard. You can use it, but we will not maintain it unless the API is improved (feel free to PR!).
PromiseKit EventKit Extensions 
This project adds promises to Apple’s EventKit framework.
CocoaPods
pod "PromiseKit/EventKit" ~> 6.0
The extensions are built into PromiseKit.framework thus nothing else is needed.
Carthage
github "PromiseKit/EventKit" ~> 3.0
The extensions are built into their own framework:
// swift
import PromiseKit
import PMKEventKit
// objc
@import PromiseKit;
@import PMKEventKit;