Deduce that $\displaystyle \displaystyle\sum_{i=1}^n \frac{1}{n+i}\to log 2 $ as $\displaystyle n \to \infty $

How on earth do i "deduce this"?! I've tried using $\displaystyle f(x) = \frac{1}{1 + x} $ but that didn't really get me anywhere...

Thanks in advance!