nginx-golang-postgres: add dev envs config (#275)

* Add Docker Desktop Development Environments config
* Upgrade to Go 1.18
* Replace nginx build with image + read-only bind mount

Signed-off-by: Milas Bowman <milas.bowman@docker.com>

nginx-golang-postgres/README.md

@@ -7,29 +7,36 @@ Project structure:
 ├── backend
 │   ├── Dockerfile
 │   ├── go.mod
+│   ├── go.sum
 │   └── main.go
 ├── db
 │   └── password.txt
 ├── compose.yaml
 ├── proxy
-│   ├── conf
-│   └── Dockerfile
+│   └── nginx.conf
 └── README.md
 ```
 
 [_compose.yaml_](compose.yaml)
-```
+```shell
 services:
   backend:
-    build: backend
+    build:
+      context: backend
+      target: builder
     ...
   db:
     image: postgres
     ...
   proxy:
-    build: proxy
+    image: nginx
+    volumes:
+      - type: bind
+        source: ./proxy/nginx.conf
+        target: /etc/nginx/conf.d/default.conf
+        read_only: true
     ports:
-    - 80:80
+      - 80:80
     ...
 ```
 The compose file defines an application with three services `proxy`, `backend` and `db`.
@@ -38,7 +45,7 @@ Make sure port 80 on the host is not already being in use.
 
 ## Deploy with docker compose
 
-```
+```shell
 $ docker compose up -d
 Creating network "nginx-golang-postgres_default" with the default driver
 Pulling db (postgres:)...
@@ -55,21 +62,32 @@ Creating nginx-golang-postgres_proxy_1   ... done
 ## Expected result
 
 Listing containers must show three containers running and the port mapping as below:
-```
-$ docker ps
-CONTAINER ID        IMAGE                           COMMAND                  CREATED             STATUS              PORTS                NAMES
-5e3ecd0289c0        nginx-golang-postgres_proxy     "nginx -g 'daemon of…"   48 seconds ago      Up 48 seconds       0.0.0.0:80->80/tcp   nginx-golang-postgres_proxy_1
-ffa1410b1c8a        nginx-golang-postgres_backend   "/server"                49 seconds ago      Up 48 seconds       8000/tcp             nginx-golang-postgres_backend_1
-e63be7db7cbc        postgres                        "docker-entrypoint.s…"   49 seconds ago      Up 49 seconds       5432/tcp             nginx-golang-postgres_db_1
+```shell
+$ docker compose ps
+NAME                              COMMAND                  SERVICE             STATUS              PORTS
+nginx-golang-postgres-backend-1   "/code/bin/backend"      backend             running
+nginx-golang-postgres-db-1        "docker-entrypoint.s…"   db                  running (healthy)   5432/tcp
+nginx-golang-postgres-proxy-1     "/docker-entrypoint.…"   proxy               running             0.0.0.0:80->80/tcp
 ```
 
 After the application starts, navigate to `http://localhost:80` in your web browser or run:
-```
+```shell
 $ curl localhost:80
 ["Blog post #0","Blog post #1","Blog post #2","Blog post #3","Blog post #4"]
 ```
 
 Stop and remove the containers
-```
+```shell
 $ docker compose down
 ```
+
+## Use with Docker Development Environments
+
+You can use this sample with the Dev Environments feature of Docker Desktop.
+
+![Screenshot of creating a Dev Environment in Docker Desktop](../dev-envs.png)
+
+To develop directly on the services inside containers, use the HTTPS Git url of the sample:
+```
+https://github.com/docker/awesome-compose/tree/master/nginx-golang-postgres
+```