Add ToJSON and FromJSON for Textarea (fixes #738)

yesod-form/Yesod/Form/Fields.hs

@@ -170,7 +170,7 @@ $newline never
 -- | A newtype wrapper around a 'Text' that converts newlines to HTML
 -- br-tags.
 newtype Textarea = Textarea { unTextarea :: Text }
-    deriving (Show, Read, Eq, PersistField, Ord)
+    deriving (Show, Read, Eq, PersistField, Ord, ToJSON, FromJSON)
 instance PersistFieldSql Textarea where
     sqlType _ = SqlString
 instance ToHtml Textarea where

yesod-form/yesod-form.cabal

@@ -1,5 +1,5 @@
 name:            yesod-form
-version:         1.3.8.3
+version:         1.3.9
 license:         MIT
 license-file:    LICENSE
 author:          Michael Snoyman <michael@snoyman.com>