fix: calling avvio with new (#230)

boot.js

@@ -101,14 +101,12 @@ function Boot (server, opts, done) {
 
   opts = opts || {}
 
-  if (!(this instanceof Boot)) {
-    const instance = new Boot(server, opts, done)
-
-    if (server) {
-      wrap(server, opts, instance)
-    }
+  if (!new.target) {
+    return new Boot(server, opts, done)
+  }
 
-    return instance
+  if (server) {
+    wrap(server, opts, this)
   }
 
   if (opts.autostart !== false) {

test/basic.test.js

@@ -97,7 +97,7 @@ test('boot a plugin with a custom server', (t) => {
   })
 })
 
-test('custom instance should inherits avvio methods', (t) => {
+test('custom instance should inherits avvio methods /1', (t) => {
   t.plan(6)
 
   const server = {}
@@ -126,6 +126,35 @@ test('custom instance should inherits avvio methods', (t) => {
   })
 })
 
+test('custom instance should inherits avvio methods /2', (t) => {
+  t.plan(6)
+
+  const server = {}
+  const app = new boot(server, {}) // eslint-disable-line new-cap
+
+  server.use(function (s, opts, done) {
+    t.equal(s, server, 'the first argument is the server')
+    t.same(opts, {}, 'no options')
+    done()
+  }).after(() => {
+    t.ok('after called')
+  })
+
+  server.onClose(() => {
+    t.ok('onClose called')
+  })
+
+  server.ready(() => {
+    t.ok('ready called')
+  })
+
+  app.on('start', () => {
+    server.close(() => {
+      t.pass('booted')
+    })
+  })
+})
+
 test('boot a plugin with options', (t) => {
   t.plan(3)