chore: Created example for VM with IP forwarding enabled (#171)

* Created example for VM with IP forwarding enabled

* Generated README

Author: betsy-lichtenberg

examples/compute_instance/next_hop/README.md

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+# Instance as next hop for a route
+
+This example creates a VM instance with IP forwarding enabled so that the
+VM can forward a packet originated by another VM.
+
+To use a VM as a next hop for a route, the VM needs to receive packets that have
+destinations other than itself. Because it forwards those packets, the packet
+sources are different from its own internal IP address. To accomplish this, you
+must enable IP forwarding for the VM. When IP forwarding is enabled, Google
+Cloud does not enforce packet source and destination checking.
+
+<!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
+## Inputs
+
+| Name | Description | Type | Default | Required |
+|------|-------------|------|---------|:--------:|
+| project\_id | The Google Cloud project ID | `string` | n/a | yes |
+
+## Outputs
+
+| Name | Description |
+|------|-------------|
+| instance\_self\_link | The URI of the instance rule  being created |
+| network\_name | The name of the VPC network where the VM instance is created |
+| project\_id | Google Cloud project ID |
+
+<!-- END OF PRE-COMMIT-TERRAFORM DOCS HOOK -->

examples/compute_instance/next_hop/main.tf

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+/**
+ * Copyright 2018 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.
+ */
+
+provider "google" {
+
+  version = "~> 3.0"
+}
+
+# [START compute_vm_as_next_hop_create]
+resource "google_compute_instance" "default" {
+  project      = var.project_id # Replace this with your project ID in quotes
+  zone         = "southamerica-east1-b"
+  name         = "instance-next-hop"
+  machine_type = "e2-medium"
+  boot_disk {
+    initialize_params {
+      image = "debian-cloud/debian-9"
+    }
+  }
+  network_interface {
+    network = "default"
+  }
+  can_ip_forward = true
+}
+# [END compute_vm_as_next_hop_create]

examples/compute_instance/next_hop/outputs.tf

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+/**
+ * Copyright 2018 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.
+ */
+
+
+output "network_name" {
+  value       = google_compute_instance.default.network_interface[0].network
+  description = "The name of the VPC network where the VM instance is created"
+}
+
+output "instance_self_link" {
+  value       = google_compute_instance.default.self_link
+  description = "The URI of the instance rule  being created"
+}
+
+output "project_id" {
+  value       = google_compute_instance.default.project
+  description = "Google Cloud project ID"
+}

examples/compute_instance/next_hop/variables.tf

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+/**
+ * Copyright 2019 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.
+ */
+
+
+
+variable "project_id" {
+  description = "The Google Cloud project ID"
+  type        = string
+}

examples/compute_instance/next_hop/versions.tf

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+/**
+ * Copyright 2018 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 {
+  required_version = ">=0.12.6"
+}