Replace Ruby w/ PHP

Author: Andreas Savvides

README.md

@@ -48,7 +48,7 @@ Head over to `localhost:5000` and you should be able to see this code in action;
 All contributions are welcome; fork the repository, make your changes and open a pull request. Try to stick to the coding conventions that are already in place.
 
 At the moment, what would be most useful is adding code to show an end-to-end solution of how to use Digits. At present we only show how this is done using a Python back-end.
-Have a look at the [issue tracker](https://github.com/AnSavvides/react-digits/issues) and feel free to say you are interested to work on something that has not already been assigned. Right now we have open tickets for building [Ruby](https://github.com/AnSavvides/react-digits/issues/1), [node.js](https://github.com/AnSavvides/react-digits/issues/3), [Lua](https://github.com/AnSavvides/react-digits/issues/2) and [Go](https://github.com/AnSavvides/react-digits/issues/4) back-ends. If you want to add support for another language, feel free to open an issue!
+Have a look at the [issue tracker](https://github.com/AnSavvides/react-digits/issues) and feel free to say you are interested to work on something that has not already been assigned. Right now we have open tickets for building [PHP](https://github.com/AnSavvides/react-digits/issues/6), [node.js](https://github.com/AnSavvides/react-digits/issues/3), [Lua](https://github.com/AnSavvides/react-digits/issues/2) and [Go](https://github.com/AnSavvides/react-digits/issues/4) back-ends. If you want to add support for another language, feel free to open an issue!
 
 ## Notes