Update README to include dependency on Ruby 1.9

Closes #17

README.md

@@ -11,6 +11,9 @@ Curl version `7.27.0` and above now supports native (Darwin) SSL so the other al
 
 To list all possible options and flags, run `./build_curl --help`.
 
+> **NOTE:**  
+> These scripts require Ruby 1.9. Check out the `ruby1.8` branch if you're still running 1.8.
+
 
 ## Default configuration
 
@@ -61,6 +64,7 @@ After you've compiled the project, all you need to do is include one of the gene
 
 When you add the files to the Xcode project, Xcode will automatically add the library files to the link build stage, i.e. you just need to add the `*.a` and `*.h` files to your project and it'll all work.
 
+
 ### Required frameworks
 
 You need to add the following frameworks:
@@ -78,4 +82,4 @@ Also huge thanks to [Jonas Schnelli](https://github.com/jonasschnelli) for the p
 
 ## License
 
-Seriously? ...
+Seriously? ...