Change gitignore

As I am using el-get, it needs el-get/ dir to be ignored by git, so
recipes using git or github method can proceed correctly. Or git won't
allow Emacs to write .git dir under el-get/.
Basic setups

Currently there is the starter "init.el", and configs reside in
config.org. Not sure about what to do with the generated config.el
though. Maybe add something in gitignore.