Add docker-compose example and improve Couchbase-2.5 setup

Added a docker-compose.example.yml for Couchbase-2.5 and updated the README with usage instructions. Enhanced the Dockerfile to ensure scripts use Unix line endings and are executable, improving container reliability.

couchbase-2.5/docker-compose.example.yml

@@ -0,0 +1,16 @@
+services:
+  couchbase:
+    image: ghcr.io/tiennm99/docker-images/couchbase-2.5:latest
+    ports:
+      - "8091:8091"
+      - "8092:8092"
+      - "11210:11210"
+      - "11211:11211"
+    restart: unless-stopped
+    stdin_open: true
+    tty: true
+    volumes:
+      - couchbase_data:/opt/couchbase/var
+
+volumes:
+  couchbase_data: