update readme.

Author: jacobwilliams

README.md

@@ -50,6 +50,11 @@ The following example generates a plot of the sine function:
 
 ```
 
+Documentation
+---------------
+
+ * The API documentation for the current ```master``` branch can be found [here](http://jacobwilliams.github.io/pyplot-fortran/).  This is generated by processing the source files with [FORD](https://github.com/cmacmackin/ford).  Note that the shell script will also generate these files automatically in the ```doc``` folder, assuming you have FORD installed.
+
 See also
 ---------------
  * [Matplotlib](http://matplotlib.org)