Update README to include explicit Swift examples.

README.md

@@ -16,6 +16,8 @@ accessibility label) on all elements on the screen.
 To install GTXiLib on all the tests of a specific test class add the following
 snippet of code to it.
 
+In Objective-C. Note that GTX is installed in the class `+ (void)setUp`, not the instance `- (void)setUp`.
+
 ```objective-c
 // Include the GTXiLib umbrella header.
 
@@ -37,6 +39,17 @@ snippet of code to it.
 }
 ```
 
+In Swift. Note that GTX is installed in the class `class func setUp`, not the instance `func setUp()`.
+
+```swift
+override class func setUp() {
+  super.setUp()
+
+  let checksToBeInstalled = GTXChecksCollection.allGTXChecks()!
+    GTXiLib.install(on: GTXTestSuite(allTestsIn: self)!, checks: checksToBeInstalled, elementExcludeLists: [])
+}
+```
+
 Once installed, GTX will run all registered accessibility checks before test
 case tearDown and fail the test if any accessibility checks fail. With the above
 snippet of code your tests will now begin to catch issues where you have added