added micropost model, definied association with user model
added test to test for destroy micropost upon destroying user
added micropost partial, updated sample_data.rake with sample micropost, added micropost stylings, added validation on micropost model, and specs
added microposts_controller to run signed_in_user filter, update routes.rb, refactored signed_in_user method out to sessions_helper, wrote test
refactored error messages partial to take any object, updated home.html, wrote spec around micropost creation on homepage, updated static_pages controller
refactored user edit and new views to use new error message partial
added feed and feed_item partial, updated user spec, microposts_controller anad static pages spec
added destroy action on micropost controller, added spec, delete link to feed_item.html.erb, and micropost.html.erb