update .gitignore to ignore .db files (I.E. SQLite databases).

This .gitignore addition is more of a convention. The database naming
convention I tend to use (with SQLite) is 'FILENAME.db'. This is not included
in the stock .gitignore file generated by git.abbether. So, I have
added it here. This should stop random testing databases getting
mixed up in the repositories Git commit history.

The code at this point has the means to generate a database after a
fresh cloning of the repository.

.gitignore

@@ -5,4 +5,5 @@
 *.lx64fsl
 *.x86f
 *~
-.#*
+.#*
+*.db