README.md in benchmark_driver-output-gruff-0.1.0 vs README.md in benchmark_driver-output-gruff-0.1.1

@@ -13,18 +13,22 @@
 
 # Ubuntu
 sudo apt-get install libmagickwand-dev
 ```
 
-And install the following gem.
+And install this gem.
 
-```ruby
-gem 'benchmark_driver-output-gruff'
+```bash
+gem install benchmark_driver-output-gruff
 ```
 
 ## Usage
 
-TODO: Write usage instructions here
+Specify `-o gruff`/`--output gruff`. Then `graph.png` will be created.
+
+```
+bundle exec benchmark-driver examples/multi.yml -o gruff --rbenv '2.4.2;2.5.0'
+```
 
 ## License
 
 The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).