后台：增加后台数据库表，修复连接问题

shared/db/Api.ts

@@ -1,5 +1,5 @@
 import BaseModel from './BaseModel';
-import { index, getModelForClass, prop, DocumentType } from '@typegoose/typegoose';
+import { index, getModelForClass, prop, DocumentType, mongoose, ReturnModelType } from '@typegoose/typegoose';
 import { COUNTER } from './../consts';
 import { CounterModel } from './Counter';
 
@@ -38,6 +38,10 @@ export default class Api extends BaseModel {
 
 }
 
-export const ApiModel = getModelForClass(Api);
-
+export let ApiModel: ReturnModelType<typeof Api, {}>;
+export function loadApiModel(connect: mongoose.Connection) {
+    ApiModel = getModelForClass(Api, {
+        existingConnection: connect
+    });
+}
 export interface ApiType extends Pick<DocumentType<Api>, keyof Api> { }