bugfix: close connections at the end of app.
bugfix: close connections at the end of app.

yadimon/amos-ss15-proj3,AMOSTeam3/amos-ss15-proj3,yadimon/amos-ss15-proj3,uv48uson/amos-ss15-proj3,uv48uson/amos-ss15-proj3,uv48uson/amos-ss15-proj3,AMOSTeam3/amos-ss15-proj3,yadimon/amos-ss15-proj3,AMOSTeam3/amos-ss15-proj3,AMOSTeam3/amos-ss15-proj3,uv48uson/amos-ss15-proj3,yadimon/amos-ss15-proj3