Revert "Revert "Made ManyToOne relation in Teacher.java to School.java""

This reverts commit bb0c77d405127fcc71c2a69fabf110dba74615d4.

Conflicts:
	src/main/java/database/model/Teacher.java
Revert "Revert "Added REST endpoint for teacher-school connection, added school in teacher constructor""

This reverts commit 9a9a1138c38f3534bc5ce6f8b294c5e06a075aee.

Conflicts:
	src/main/java/database/model/Teacher.java
	src/main/java/rest/SchoolResource.java
Revert "Revert "Added school in Teacher constructor reference in TeacherResource""

This reverts commit e4759b088cbaf44259013a1672390e70241d5ec4.

Conflicts:
	src/main/java/rest/TeachersResource.java