rm alias screen, because use byobu
diet bash history

ref : http://takuya-1st.hatenablog.jp/entry/20090828/1251474360
chg : git config --global push.default simple

ref : http://dqn.sakusakutto.jp/2012/10/git_push.html
add : alias pullup
add : git log alias

  ref : http://blog.toshimaru.net/git-log-graph/