added migration, and shared_items created with pending: false status
can return items, sets pending to true
pending/user_id cycle complete
user can only return their own tools
two tests added to SharedItems Controller
test for confirm return
Merge branch 'master' into tool-return
added pending items to user show, fixed selection bug
added a browse all checked out tools page
Merge pull request #16 from katiespiders/tool-return

Tool return