docker-cloud.yml: add Docker stack example

Demonstrate a minimal stack with a generic volume, web host, and proxy.

Demonstrates no exposed port on the source server and the need to escape $ values in the HTPASSWD.

Author: jeremydouglass

docker-cloud.yml

@@ -0,0 +1,27 @@
+version: '3.1'
+
+volumes:
+  web-data:
+
+services:
+
+  web:
+    image: 'nginx'
+    ## instead of an exposed port use FORWARD_PORT below
+    # ports:
+    #   - '80:80'
+    volumes:
+      - web-data:/usr/share/nginx/html:ro
+  
+  auth:
+    image: 'beevelop/nginx-basic-auth'
+    links:
+      - 'web'
+    ports:
+      - '8080:80'
+    environment:
+      - PORT=80
+      - FORWARD_HOST=web
+      - FORWARD_PORT=80
+      ## escape $ with $$ in Docker yml due to variable expansion
+      - HTPASSWD=foo:$$apr1$$odHl5EJN$$KbxMfo86Qdve2FH4owePn.