TypeError in FacebooksController#create

Rails
1

I am using fb_graph gem to post something on my wall. I am getting this
error while using fb_graph -can’t dump hash with default proc. This is
the
code -

def show
auth = Facebook.auth.from_cookie(cookies)
authenticate Facebook.identify(auth.user)
redirect_to root_url
end

handle Normal OAuth flow: start

def new
client = Facebook.auth(callback_facebook_url).client
redirect_to client.authorization_uri(
:scope => Facebook.config[:scope]
)
end

handle Normal OAuth flow: callback

def create
(0…2).each do
begin
client = Facebook.auth(callback_facebook_url).client
client.authorization_code = params[:code]
access_token = client.access_token! :client_auth_body
user = FbGraph::User.me(access_token).fetch
authenticate Facebook.identify(user)
redirect_to “/”
break
rescue Exception => e
end
end
end

I am getting TypeError in FacebooksController#create