从一组给定的电影描述中，识别出所有的爱情电影，并按照评分排序。
[{name: "肖申克的救赎", genres:["drama", "crime"], rating: 9.3},
 {name: "泰坦尼克号", genres:["romance", "drama", "history"], rating: 7.8},
 {name: "爱在午夜降临前", genres:["drama", "romance", "comedy"], rating: 8.1},
 {name: "暮光之城", genres:["fantasy", "romance", "drama"], rating: 5.7}]
爱情电影列表按评分排序：
1. 爱在午夜降临前 (8.1)
2. 泰坦尼克号 (7.8)