Fix inconsistent table name.
Update core.clj
Update core_test.clj
Merge pull request #2 from nbeloglazov/master

Исправить название таблицы на clients.
Fixed clients instead of client
Merge branch 'master' of https://github.com/dbushenko/clojure_course_task03

Conflicts:
	src/clojure_course_task03/core.clj
Fixed 'clients' instead of 'client'