adds json fixture to test storage

spec/fixtures/files/auth_stored_credentials.json

@@ -0,0 +1,10 @@
+{
+  "access_token":"my_access_token",
+  "authorization_uri":"https://accounts.google.com/o/oauth2/auth",
+  "client_id":"123456_test_client_id@.apps.googleusercontent.com",
+  "client_secret":"123456_client_secret",
+  "expires_in":3600,
+  "refresh_token":"my_refresh_token",
+  "token_credential_uri":"https://accounts.google.com/o/oauth2/token",
+  "issued_at":1384440275
+}