ignore executable file

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>
finished tour8

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>
finished tour9

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>
finished tour10

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>
finished tour11

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>
finished tour12

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>
finished tour13

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>