Merge pull request #35 from YfLn/master

Updating Richard branch from master
Merge pull request #36 from YfLn/master

Updating Richard branch from master
-added check for Database to see if it is already in user's portfolio or not
-added 'Add Database'/'Remove Database From Portfolio' button to View Database page.
Merge pull request #37 from YfLn/Richard

Check for unique database in portfolio, remove database from portfolio