Transaction 추가 및 로그인, 회원가입 validate 적용, backend api 라우터 정리

backend 전체적인 부분과 frontend의 로그인/회원가입 최종 수정입니다.

backend/models/Book.js

@@ -9,40 +9,9 @@ const BookSchema = new Schema({
   major: { type: String },
   type: { type: String },
   src: { type: String },
-  seller: [
-    {
-      seller_id: { type: String },
-      on_transaction: { type: Boolean }
-    }
-  ],
-
   stock: { type: Number }
 });
 
-BookSchema.statics.create = function(Book_info) {
-  const {
-    title,
-    grade,
-    major,
-    type,
-    src,
-    stock,
-    seller: []
-  } = Book_info;
-
-  const Book = new this({
-    title,
-    grade,
-    major,
-    type,
-    src,
-    stock,
-    seller: []
-  });
-  // return the Promise
-  return Book.save();
-};
-
 autoInc.initialize(mongoose.connection);
 BookSchema.plugin(autoInc.plugin, "Book");