Added lume.weightedchoice()

README.md

@@ -64,6 +64,17 @@ raised.
 lume.randomchoice({true, false}) -- Returns either true or false
 ```
 
+### lume.weightedchoice(t)
+Takes the argument table `t` where the keys are the possible choices and the
+values are the choice's weight. A weight should be 0 or above, the larger the
+weight value the higher the probability of that choice being picked. If the
+table is empty or all the weights are 0 or a weight is below zero an error is
+raised.
+```lua
+lume.weightedchoice({ ["cat"] = 10, ["dog"] = 5, ["frog"] = 0 })
+-- Returns either "cat" or "dog" with "cat" being twice as likely to be chosen.
+```
+
 ### lume.shuffle(t)
 Shuffles the values of array `t` in place, returns the array.