added solution to AuthenticationService and UserService(method findBy…#1246

DianaKiyan wants to merge 1 commit intomate-academy:mastermate-academy/jv-oop-lesson-0:masterfrom

DianaKiyan:bonus-task-solutionDianaKiyan/jv-oop-lesson-0:bonus-task-solutionCopy head branch name to clipboard