Update ReadMe

Author: ValentinH

README.md

@@ -187,6 +187,7 @@ The default options are:
     minRange: 0,
     id: null,
     translate: null,
+    getLegend: null,
     stepsArray: null,
     draggableRange: false,
     draggableRangeOnly: false,
@@ -257,9 +258,21 @@ $scope.slider = {
 };
 ```
 
+**getLegend** - _Function(value, sliderId)_: Use to display legend under ticks. The function will be called with each tick value and returned content will be displayed under the tick as a legend. If the returned value is null, then no legend is displayed under the corresponding tick.
+
 **id** - _Any (defaults to null)_: If you want to use the same `translate` function for several sliders, just set the `id` to anything you want, and it will be passed to the `translate(value, sliderId)` function as a second argument.
 
-**stepsArray** - _Array_: If you want to display a slider with non linear/number steps. Just pass an array with each slider value and that's it; the floor, ceil and step settings of the slider will be computed automatically. The `rz-slider-model` value will be the index of the selected item in the stepsArray.
+**stepsArray** - _Array_: If you want to display a slider with non linear/number steps.
+Just pass an array with each slider value and that's it; the floor, ceil and step settings of the slider will be computed automatically. The `rz-slider-model` value will be the index of the selected item in the stepsArray.
+
+`stepsArray` can also be an array of objects like:
+
+```js
+[
+  {value: 'A'}, // the display value will be *A*
+  {value: 10, legend: 'Legend for 10'} // the display value will be 10 and a legend will be displayed under the corresponding tick.
+]
+```
 
 **draggableRange** - _Boolean (defaults to false)_: When set to true and using a range slider, the range can be dragged by the selection bar. *Applies to range slider only.*