Test: Extract a method that creates a new user for test
Test: Extract a method that creates a new thread for test
Test: Extract a method that creats a new response for test
Test: Use helper methods
Test: Suppress warnings

under warnings occured.
Unquoted string "board" may clash with future reserved word at t/Util.pm
line 48.
Unquoted string "board" may clash with future reserved word at t/Util.pm
line 60.
Unquoted string "board" may clash with future reserved word at t/Util.pm
line 72.
Merge pull request #50 from oguro1021/fix_tests_3

Test: Extract a method that creates new entity for test