teacher, course, assignment, lecturenote created

"rails generate scaffold Teacher first_name:string last_name:string
office:string email:string"
"rails generate scaffold Course title:string description:string
syllabus:string teacher_id:integer"
"rails generate scaffold Assignment title:string description:string
duedate:string course_id:integer"
"rails generate scaffold Lecturenote title:string content:string
course_id:integer"
"bundle exec rake db:migrate"