README.md in rails-erd-1.7.0 vs README.md in rails-erd-1.7.1

- old
+ new

@@ -30,9 +30,11 @@
 
 See the [installation instructions](https://voormedia.github.io/rails-erd/install.html) for a complete description of how to install Rails ERD. Here's a summary:
 
 * Install Graphviz 2.22+ ([how?](https://voormedia.github.io/rails-erd/install.html)). On macOS with Homebrew run `brew install graphviz`.
 
+* on linux - `sudo apt-get install graphviz`
+
 * Add <tt>gem 'rails-erd', group: :development</tt> to your application's Gemfile
 
 * Run <tt>bundle exec erd</tt>
 
 ### Configuration