How to solve differential equation $f'(x) = f(x) - f(x-1) $ with $f(0)= 0$

Question

How can I solve the ODE:

$f'(x) = f(x) - f(x-1)$ where $f(0)= 0$, and $x \geq 0$

Note: I am trying to solve a problem where it came up and I haven't done DE for years and thus not sure where to start.