Tag name should be unique, so make the tag name to be the primary key of the Tag table
Remove autoincrement int key in itemtag table, use tagId and itemId as primary key
Rename db name from ItemTag to TagItem
Add Tag_item function
Change insert to replace to handle the case where the tag already exists
Rename ItemTagDBManager to TagItemDBManager
Add Tag option to the item context menu
Add AddTag activity and its layout
Get all tags and display them in AddTag view
Refactor
Add action bar in AddTag view
add tag ui update