Add Technical Documentation (#176)

This PR adds the technical documentation to the repository since the previously used link doesn't point to the documentation anymore. Thanks to @torpedro.

Author: mweisgut

README.md

@@ -6,7 +6,7 @@ C++ SQL Parser
 This is a SQL Parser for C++. It parses the given SQL query into C++ objects.
 It has been developed for integration in [Hyrise](https://github.com/hyrise/hyrise), but can be used perfectly well in other environments as well.
 
-In March 2015 we've also written a short paper outlining discussing some development details and the integration into our database Hyrise. You can find the paper [here](http://torpedro.com/paper/HyriseSQL-03-2015.pdf).
+In March 2015 we've also written a short paper outlining discussing some development details and the integration into our database Hyrise. You can find the paper [here](docs/technical_documentation.pdf).
 
 
 ## Usage