adds makefile and update db image

Makefile

@@ -1,2 +1,11 @@
-build:
-	docker build --no-cache --rm -t airflow_compose:latest .
+compile:
+	docker-compose build
+
+start:
+	docker-compose up -d
+
+stop:
+	docker-compose down
+
+run: compile \
+	start

docker-compose.yml

@@ -2,7 +2,7 @@ version: '3'
 services:
   postgres:
     container_name: airflowmeta_example
-    image: postgres:9.6.3
+    image: postgres:9.6.3-alpine
     environment:
       POSTGRES_PASSWORD: airflow123
       POSTGRES_USER: airflow
@@ -33,4 +33,4 @@ services:
     depends_on:
       - postgres
     links:
-      - postgres:postgres
+      - postgres:postgres