Issues surrounding the ownership of online teaching materials are still being decided. If you are affiliated with an institution, you will want to check their policies on ownership of materials. If you create this course during work time, does the institution own the content? Is this something you can make money from offering? Are there exceptions to the rules? It is best to know your environment and policies before you invest the effort into creating something and learning that you cannot use it the way you intended. If you are partnering with a university, you should also check their policies.