Use a relational database to store the algorithms


Now the algorithms are stored in an XML file. It's not easy to manage the relations between different objects (such as algorithm and group). From version 1.3, the program will also store user's time. So it's more like a database from now on. So I would like to finalize the algorithm storage and user profile storage to a relational database.
The XML schema can be used to export/import algorithms. So it's better to preserve this functionality.