update paperclip file restriction rule, only disallow[: , \ , /]
update paperclip file restriction rule, only disallow[: , \ , /]

dariusf/coursemology.org,allenwq/coursemology.org,allenwq/coursemology.org,dariusf/coursemology.org,nnamon/coursemology.org,dariusf/coursemology.org,Coursemology/coursemology.org,Coursemology/coursemology.org,dariusf/coursemology.org,nusedutech/coursemology.org,Coursemology/coursemology.org,nusedutech/coursemology.org,nnamon/coursemology.org,dariusf/coursemology.org,nnamon/coursemology.org,allenwq/coursemology.org,Coursemology/coursemology.org,Coursemology/coursemology.org,nnamon/coursemology.org,nnamon/coursemology.org,nusedutech/coursemology.org,nusedutech/coursemology.org,nusedutech/coursemology.org,allenwq/coursemology.org,allenwq/coursemology.org