Connections between tables in database were modifyed.
Added new picture and Workbench file of mapped DB.

 Changes to be committed:
	renamed:    ext-resources/maped_school.mwb -> ext-resources/archive/mapped_school.mwb
	new file:   ext-resources/mapped.mwb
	new file:   ext-resources/mapped_pic.png
	modified:   school-model/src/main/java/school/model/CourseRequest.java
	modified:   school-model/src/main/java/school/model/Lesson.java
	modified:   school-model/src/main/java/school/model/Message.java
	modified:   school-model/src/main/java/school/model/Parent.java
	modified:   school-model/src/main/java/school/model/Room.java
	modified:   school-model/src/main/java/school/model/Salary.java
	modified:   school-model/src/main/java/school/model/Schedule.java
	modified:   school-model/src/main/java/school/model/Student.java
	modified:   school-model/src/main/java/school/model/Subject.java
	modified:   school-model/src/main/java/school/model/Teacher.java