update syntax of form_for to rails 3.2.8
(grafted from 17d48b004affe1e1dd4a981d9beef9d61ce83078)

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extra : source : 17d48b004affe1e1dd4a981d9beef9d61ce83078
Merge pull request #1 from nattee/master

update syntax of form_for to rails 3.2.8. Fix "message cannot be replied by Admin"