Reword rake-fast README, add lib/tasks information

plugins/rake-fast/README.md

@@ -2,22 +2,34 @@
 
 Fast rake autocompletion plugin.
 
-This script caches the output for later usage and significantly speeds it up. It generates a .rake_tasks cache file in parallel to the Rakefile. It also checks the file modification dates to see if it needs to regenerate the cache file.
+This plugin caches the output for later usage and significantly speeds it up.
+It generates a `.rake_tasks` cache file in parallel to the Rakefile. It also
+checks the file modification time to see if it needs to regenerate the cache
+file.
 
-This is entirely based on [this pull request by Ullrich Schäfer](https://github.com/robb/.dotfiles/pull/10/), which is inspired by [this Ruby on Rails trick from 2006](http://weblog.rubyonrails.org/2006/3/9/fast-rake-task-completion-for-zsh/).
+This is entirely based on [this pull request by Ullrich Schäfer](https://github.com/robb/.dotfiles/pull/10/),
+which is inspired by [this Ruby on Rails trick from 2006](http://weblog.rubyonrails.org/2006/3/9/fast-rake-task-completion-for-zsh/).
 
 Think about that. 2006.
 
+----------
+
+Since August of 2016, it also checks if it's in a Rails project and looks at
+rake files inside `lib/tasks` and their modification time to know if the
+cache file needs to be regenerated.
+
 ## Installation
 
 Just add the plugin to your `.zshrc`:
 
-```bash
+```zsh
-plugins=(foo bar rake-fast)
+plugins=(... rake-fast)
 ```
 
 You might consider adding `.rake_tasks` to your [global .gitignore](https://help.github.com/articles/ignoring-files#global-gitignore)
 
 ## Usage
 
-`rake`, then press tab
+Type `rake`, then press tab.
+
+If you want to force the regeneration of the `.rake_tasks` file, run `rake_refresh`.