Solving ODE: $\dot{r}=\sqrt{\frac{a}{r}+b}$

[NoobixCube]

Hi guys,
Could anyone suggest a method to solve this ODE w.r.t. time?
<br /> \dot{r}=\sqrt{\frac{a}{r}+b}<br />

 

[NoobixCube]

I have managed to find one