Update README.md

Added Xcode 6 Beta 6 notice.

README.md

@@ -5,6 +5,10 @@ Federal Data SDK built in the Swift programming language
 
 Until the Swift language becomes more stable, consider this a beta release.  See the Release notes for more information.
 
+### Xcode 6 Beta 6 Notice
+If you've recently upgraded to Beta 6 and you're getting weird errors, [follow the steps outlined here](http://rshankar.com/apple-mach-o-linker-error-xcode-6-beta-6/).
+
+
 ### Documentation
 Documentation for this SDK can be found at [http://USDepartmentofLabor.github.io/Swift-Federal-Data-SDK](http://USDepartmentofLabor.github.io/Swift-Federal-Data-SDK).