I added Student and Instructor models. I readded the registration form.
I deleted the view/devise folder and replaced with the user folder
I added a sign-in partial form for the sign-in dropdown. I also updated
some view/users files.
Merge branch 'th-working'
Revert "Merge branch 'th-working'"

This reverts commit 54436aa0983f01db3a6e94e37549f3d4ff80c258, reversing
changes made to ff17de9b43d3fcf40cee1df43c19c6a8764ae795.