New pubsub module (#73)

* pubsub module, untested

* fixed a few errors

modules/pubsub/outputs.tf

@@ -0,0 +1,46 @@
+/**
+ * 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.
+ */
+
+output "id" {
+  description = "Topic id."
+  value       = google_pubsub_topic.default.id
+}
+
+output "subscriptions" {
+  description = "Subscription resources."
+  value       = google_pubsub_subscription.default
+  depends_on = [
+    google_pubsub_subscription_iam_binding.default
+  ]
+}
+
+output "subscription_id" {
+  description = "Subscription ids."
+  value = {
+    for k, v in google_pubsub_subscription.default : k => v.id
+  }
+  depends_on = [
+    google_pubsub_subscription_iam_binding.default
+  ]
+}
+
+output "topic" {
+  description = "Topic resource."
+  value       = google_pubsub_topic.default
+  depends_on = [
+    google_pubsub_topic_iam_binding.default
+  ]
+}