added demo script

demo/example.js

@@ -0,0 +1,19 @@
+const ewelink = require('../main');
+
+(async () => {
+  const conn = new ewelink({
+    email: '<your ewelink email>',
+    password: '<your ewelink password>',
+  });
+
+  /* get all devices */
+  const devices = await conn.getDevices();
+  console.log(devices);
+
+  /* get specific devide info */
+  const device = await conn.getDevice('<your device id>');
+  console.log(device);
+
+  /* toggle device */
+  await conn.toggleDevice('<your device id>');
+})();

package.json

@@ -4,7 +4,7 @@
   "description": "eWeLink API for Node.js",
   "main": "main.js",
   "scripts": {
-    "test": "echo \"Error: no test specified\" && exit 1"
+    "demo": "node ./demo/example.js"
   },
   "author": "Martín M.",
   "license": "MIT",