Though we all know you shouldn't store API keys, passwords, or email addresses in your repositories, it's still common practice for many developers. It's just easier, right? You shouldn't feel bad if you have done this, but consider this post an opportunity to learn how to do it right.
Former Indie iOS Focus Weekly sponsor BuddyBuild is also mentioned. Using their Secure Files API, you can store any credentials without exposing them.
Secret variables in Xcode AND your CI for fun and profit by Robin Malhotra