Please review my logical data model
I have a few general points.

Firstly, your diagram is a bit confusing! There are lines which merge into each other and the source and destination tables aren't clear.

Secondly (and this is a matter of opinion), you might want to use &lt;table_name&gt;_id as your PRIMARY KEY (e.g. ticket_id). It removes ambiguity, makes debugging easier and SQL easier to write and particularly read. My own personal convention is to use lower_case_with_underscores_id (and lower case for identifiers generally) and UPPER CASE FOR SQL. This makes code a pleasure to read and almost self-parsing.

Also, take a look here, it's from databaseanswers.org which can be a good first port of call for database modelling projects! Try and make your diagram look a little bit more like that!

Finally, you can download F/LOSS applications for bug-tracking - there's more of them than you can shake a stick at! Again, personal recommendation, you should look at Fossil - it's by D. Richard Hipp, the same guy who's given the world SQLite! 

I've watched some podcasts by him and he's impressive! At least take a look at his schema - you can be sure that thought went into it! It's BSD licenced, but I'm not sure if your professor/lecturer would be happy about you claiming his work as your own, but if you clearly refer to it, that should be OK! :-) 

Be prepared to make a lot of changes - as Helmuth Von Moltke said, "no plan survives contact with the enemy" - best of luck with your project!