Added range multiplier to Readme

README.md

@@ -61,6 +61,13 @@ the specified range and will generate a benchmark for each such argument.
 BENCHMARK(BM_memcpy)->Range(8, 8<<10);
 ```
 
+By default the arguments in a range are generated in multiples of eight and the command above selects [ 8, 64, 512, 4k, 8k ]. In the following code the range multiplier is changed to multiples of two.
+
+```c++
+BENCHMARK(BM_memcpy)->RangeMultiplier(2)->Range(8, 8<<10);
+```
+Now the arguments generated are [ 8, 16, 32, 64, 128, 256, 512, 1024, 2k, 4k, 8k ].
+
 You might have a benchmark that depends on two inputs. For example, the
 following code defines a family of benchmarks for measuring the speed of set
 insertion.