Update API documentation : Create User

[kelumsampath]

create new user end-point is now implemented.
https://dev-dot-intecs-webapp.el.r.appspot.com/users (post request)
json body:

{
	"createdBy":"123",
	"email":"example@gmail.com"
}

then user will register to the system and password will send to entered email. (in here "example@gmail.com")

update swagger API documentation for users (post) request in swagger.json