[controller] add department to exams
[view] fields for showing department in exams
[model] department exam assoc
[spec/model] department exam assoc
[migrate] add department_id in exams table
[spec/request] test behavior of department to exams and exams assigning syllabus department
[spec/controller] test load_data method for loading @departments where is needed
Merge pull request #239 from Genshin/add_departments_to_exam

Add departments to exam