Late on this as well but in case it's useful to you, I use this for quick "git add":

  ga () {
          if test "$#" -eq 0
          then
                  echo "No arguments (0_0)?"
          elif test "$#" -eq 1
          then
                  git add -u && git commit -m "$(echo $1 | sed 's/^./\U&\E/')"
          else
                  git add ${@:1:$(( $# - 1 ))} && git commit -m "$(echo ${@:$#} | sed 's/^./\U&\E/')"
          fi
  }

Usage:

  # Add all modified files and capitalize the commit message
  ga "fix typo in README"
  # Add some files and treat last arg as commit message
  ga main.rs point.rs "speedup by 10e9"