add config for ecr repo and remote backend

terraform/ecr-repo.tf

@@ -0,0 +1,9 @@
+resource "aws_ecr_repository" "myapp-repo" {
+  name = "myapp"
+
+  # defaults
+  image_tag_mutability = "MUTABLE"  
+  image_scanning_configuration {
+    scan_on_push = true
+  }
+}