Updated DB class

Created update methods
Created instances of some classes
Merge remote-tracking branch 'origin/master'

Conflicts:
	src/team4/retailsystem/model/LineItem.java
	src/team4/retailsystem/model/Product.java
Revert "Merge remote-tracking branch 'origin/master'"

This reverts commit 928d63035b823b1fc08178010b878d24afa9d498.
Revert "Updated DB class"

This reverts commit b0391c4944ef6a272613b29821139e7c19c778aa.