add build.sh command to verify that CocoaPods
add build.sh command to verify that CocoaPods

pulls CocoaPods with the `sha` environment variable if present, `master`
otherwise.

tenebreux/realm-cocoa,tenebreux/realm-cocoa,ul7290/realm-cocoa,ul7290/realm-cocoa,tenebreux/realm-cocoa,ul7290/realm-cocoa,ul7290/realm-cocoa,tenebreux/realm-cocoa,ul7290/realm-cocoa,tenebreux/realm-cocoa