****Add posts model***
****relation user & microposts ***
****add posts partial layout ***
****add posts partial layout ***
****add posts seed ***
****add content for partial layout ***
****move signed_in_user from usercontroller to  session_helper ***
**** add css for posts ***
**** add microposts controller ***
**** add microposts controller ***
****change view to distinguish user logined in or not ***
****siderbar user info ***
****trasfer object to show errors***
****get signedin user's posts ***
**** posts create form ***
****add patial layout to show userinfo ***
****use patial layout to show posts ***
****update user new&edit form to show errors***
****posts create action ***
****add feeds  instance varies  ***