Performance Issues - Optimisations required.

[tiagomiguelcs]

For a high number of stored sessions, several performance-related issues are identified (i.e., slowdowns) - Optimisations are required.

This SQL dump file can be used to replicate the problem.

[Joana-Cabral]

Optimizations were done to the function add_session in session.py, no performance issues were found when starting a new session, while using the SQL dump file.

[Joana-Cabral]

Optimize the function used for gathering information about previous sessions for a specific user ("My Sessions").