NoMethodError - undefined method `push'

[soramugi]

googleの認証トークンの設定でGoogle+ APIを有効にしてないと内部エラーのページが表示されます

Started GET "/users/sign_in" for 127.0.0.1 at 2015-09-02 15:18:50 +0900
Processing by Devise::SessionsController#new as HTML
Completed 500 Internal Server Error in 2ms

NoMethodError - undefined method `push' for #<String:0x007fec86e285b8>:
  gritter (1.1.0) lib/gritter/gflash.rb:58:in `gflash_push'
  gritter (1.1.0) lib/gritter/gflash.rb:38:in `block in gflash'
  gritter (1.1.0) lib/gritter/gflash.rb:28:in `gflash'
  app/controllers/application_controller.rb:13:in `redirect_unless_signed_in'
  activesupport (4.1.8) lib/active_support/callbacks.rb:424:in `block in make_lambda'
  activesupport (4.1.8) lib/active_support/callbacks.rb:160:in `block in halting'
  activesupport (4.1.8) lib/active_support/callbacks.rb:166:in `block in halting'
  activesupport (4.1.8) lib/active_support/callbacks.rb:229:in `block in halting'

flash[:alert]に文字列が入っているのにapplication_controller.rbファイル内のgflash alert: 'You need Login!'で配列を入れようとしているのが原因のエラーのようです。

flash[:alert] # "Could not authenticate you from GoogleOauth2 because \"Invalid credentials\"."

ちなみにapi認証エラーのログも出力されてました

Started GET "/users/auth/google_oauth2/callback?state=xxxxxxx&code=xxxxxxx" for 127.0.0.1 at 2015-09-02 15:22:17 +0900
I, [2015-09-02T15:22:26.076934 #14971]  INFO -- omniauth: (google_oauth2) Callback phase initiated.
E, [2015-09-02T15:22:26.781059 #14971] ERROR -- omniauth: (google_oauth2) Authentication failure! invalid_credentials: OAuth2::Error, {"errors"=>[{"domain"=>"usageLimits", "reason"=>"accessNotConfigured"
, "message"=>"Access Not Configured. The API (Google+ API) is not enabled for your project. Please use the Google Developers Console to update your configuration.", "extendedHelp"=>"https://console.devel
opers.google.com"}], "code"=>403, "message"=>"Access Not Configured. The API (Google+ API) is not enabled for your project. Please use the Google Developers Console to update your configuration."}: 
{
 "error": {
  "errors": [
   {
    "domain": "usageLimits",
    "reason": "accessNotConfigured",
    "message": "Access Not Configured. The API (Google+ API) is not enabled for your project. Please use the Google Developers Console to update your configuration.",
    "extendedHelp": "https://console.developers.google.com"
   }
  ],
  "code": 403,
  "message": "Access Not Configured. The API (Google+ API) is not enabled for your project. Please use the Google Developers Console to update your configuration."
 }
}