Fixed "problem" JST to GMT.
Revert "Merge pull request #1 from moznion/fix/must_be_JST"

This reverts commit 74d7b17abae69c7db72e3857a6fd412b18678860, reversing
changes made to 1e9c9c4d0df46321e553b8967a27902bbcd6f852.
Fixed the "problem" JST to GMT. Because timezone problem is not only essential but hard. We judged that timezone problem do not suit for pre intern exercise.