Document why the podspec is on the root of the repo
diff --git a/Protobuf.podspec b/Protobuf.podspec
index 5c154a5..c98dae4 100644
--- a/Protobuf.podspec
+++ b/Protobuf.podspec
@@ -1,3 +1,8 @@
+# This file describes to Cocoapods how to integrate the Objective-C runtime into a dependent
+# project.
+# Despite this file being specific to Objective-C, it needs to be on the root of the repository.
+# Otherwise, Cocoapods gives trouble like not picking up the license file correctly, or not letting
+# dependent projects use the :git notation to refer to the library.
Pod::Spec.new do |s|
s.name = 'Protobuf'
s.version = '3.0.0'