Add Docker setup, add environment vars for each flag

docker-compose.yml

@@ -0,0 +1,26 @@
+services:
+  aggregator:
+    build: .
+    image: git.ipng.ch/ipng/nginx-logtail
+    command: ["/usr/local/bin/aggregator"]
+    restart: unless-stopped
+    environment:
+      AGGREGATOR_LISTEN: ":9091"
+      AGGREGATOR_COLLECTORS: ""   # e.g. "collector1:9090,collector2:9090"
+      AGGREGATOR_SOURCE: ""       # defaults to container hostname
+    ports:
+      - "9091:9091"
+
+  frontend:
+    image: git.ipng.ch/ipng/nginx-logtail
+    command: ["/usr/local/bin/frontend"]
+    restart: unless-stopped
+    environment:
+      FRONTEND_LISTEN: ":8080"
+      FRONTEND_TARGET: "aggregator:9091"
+      FRONTEND_N: "25"
+      FRONTEND_REFRESH: "30"
+    ports:
+      - "8080:8080"
+    depends_on:
+      - aggregator