Revert "Merge logic."

This reverts commit 29ee70e119a81dd1df4509c0311fbf070990ab33.
Revert "Removing courses when updating the app settings."

This reverts commit 5707e003d919afafbbebf7561a3b3a3e1ca81cd4.
Revert "Adding courses properly."

This reverts commit 7c4e9b7fabb457da4d3df2b8108c61a570dca7d2.
Un-merge logic.
Batch processing to adding course.