Add example docker-compose.yaml for Postgres

docker-compose.pgsql.yml

@@ -0,0 +1,26 @@
+version: "3.0"
+services:
+  limesurvey:
+    build:
+      context: apache/
+      dockerfile: Dockerfile
+    volumes:
+      - /tmp/upload/:/var/www/html/upload/
+    links:
+      - lime-db
+    depends_on:
+      - lime-db
+    ports:
+      - "8080:80"
+    environment:
+      - "DB_TYPE=pgsql"
+      - "DB_PORT=5432"
+      - "DB_HOST=docker-limesurvey_lime-db_1"
+      - "DB_PASSWORD=secret"
+      - "ADMIN_PASSWORD=foobar"
+  lime-db:
+    image: postgres:10
+    environment:
+      - "POSTGRES_USER=limesurvey"
+      - "POSTGRES_DB=limesurvey"
+      - "POSTGRES_PASSWORD=secret"