use a image as the background of the delete button
fix the delete button display problem on scrach attachement
Merge pull request #7 from soloara/refactor

refactoring lessonplans_controller test
Merge branch 'refactor'
redirect to login page when user did not login and want to create new session
add links to the ppt
refactoring comments controller and add the test
Please run test before commit!!!
fix conflict