README.md in prawn-icon-3.0.0 vs README.md in prawn-icon-3.1.0

@@ -7,10 +7,11 @@
 Prawn::Icon provides a simple mechanism for rendering icons and icon fonts from within [Prawn](https://github.com/prawnpdf/prawn).
 
 The following icon fonts ship with Prawn::Icon:
 
 * FontAwesome (http://fontawesome.io/icons/)
+* Material Design Icons (https://materialdesignicons.com/)
 * Foundation Icons (http://zurb.com/playground/foundation-icon-fonts-3)
 * PaymentFont (https://paymentfont.com)
 
 Prawn::Icon was originally written by Jesse Doyle.
 
@@ -85,9 +86,10 @@
 Currently supported prefixes include:
 
 * `fab` - [FontAwesome Brands](https://fontawesome.com/icons?d=gallery&s=brands&m=free) (eg. `fab-amazon`).
 * `far` - [FontAwesome Regular](https://fontawesome.com/icons?d=gallery&s=regular&m=free) (eg. `far-address-book`).
 * `fas` - [FontAwesome Solid](https://fontawesome.com/icons?d=gallery&s=solid&m=free) (eg. `fas-location-arrow`).
+* `mdi` - [Material Design Icons](https://materialdesignicons.com/) (eg. `mdi-beer`),
 * `fi` - [Foundation Icons](https://zurb.com/playground/foundation-icon-fonts-3) (eg. `fi-compass`).
 * `pf` - [PaymentFont](https://paymentfont.com/#icons) (eg. `pf-cash`).
 
 ## How It Works