README.md in benchmark_driver-0.10.0 vs README.md in benchmark_driver-0.10.1

@@ -2,10 +2,12 @@
 
 Fully-featured accurate benchmark driver for Ruby
 
 ## Project Status
 
-**Under Construction**
+Beta.
+
+Interface might be changed in the future, but it's almost fixed and many features can run well.
 
 ## Features
 ### Accurate Measurement
 
 - Low overhead benchmark by running generated script instead of calling Proc