fix: Renaming backend.tf to backend.tf.example as per README.md (#64)

* naming backend.tf to backend.tf.example as per README.md

* adding apache license to 0-bootstrap/backend.tf.example

Author: benking84

0-bootstrap/backend.tf.example

@@ -1,3 +1,19 @@
+/**
+ * Copyright 2020 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 terraform {
   backend "gcs" {
     bucket = "STATE_BUCKET"