refactor(core): adjust directory structure:

src/core/init/index.js

@@ -0,0 +1,27 @@
+import config from '../config'
+import { initLifecycle, callHook } from './lifecycle'
+import { initRender } from '../render'
+import { initRoute } from '../route'
+import { initEvent } from '../event'
+import { initFetch } from '../fetch'
+import { isFn } from '../util/core'
+
+export function initMixin (Docsify) {
+  Docsify.prototype._init = function () {
+    const vm = this
+    vm._config = config || {}
+
+    initLifecycle(vm) // Init hooks
+    initPlugin(vm) // Install plugins
+    callHook(vm, 'init')
+    initRender(vm) // Render base DOM
+    initEvent(vm) // Bind events
+    initRoute(vm) // Add hashchange eventListener
+    initFetch(vm) // Fetch data
+    callHook(vm, 'ready')
+  }
+}
+
+function initPlugin (vm) {
+  [].concat(vm.config.plugins).forEach(fn => isFn(fn) && fn(vm.bindHook))
+}