Conversation

1. GET /kindergarten/:kg/conversation/:phone

---

https://www.cocobabys.com/kindergarten/93740362/conversation/123456789?from=1&to=2&most=25

phone家长电话号码 from=起始id，不包括 to=结束id，不包括

[{"phone":"123456789","timestamp":1392968799188,"id":1392968799188,"content":"我很满意学校的服务",
"image":"http://suoqin-test.u.qiniudn.com/FgPmIcRG6BGocpV1B9QMCaaBQ9LK","sender":""},
{"phone":"123456789","timestamp":1392967799188,"id":1392967799188,"content":"谢谢你的鼓励",
"image":"http://suoqin-test.u.qiniudn.com/Fget0Tx492DJofAy-ZeUg1SANJ4X","sender":"带班老师", "sender_id": "13999234231"}]

sender为空表示家长发送，sender非空则表示老师发送，非空时内容为发送老师的名字, sender_id是老师电话号码，可以通过employee接口查询老师的信息

2. POST /kindergarten/:kg/conversation/:phone

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POST https://www.cocobabys.com/kindergarten/93740362/conversation/123456789

request payload：

{"phone":"123456789","timestamp":1392967799188,"content":"谢谢你的鼓励","image":"http://suoqin-test.u.qiniudn.com/Fget0Tx492DJofAy-ZeUg1SANJ4X","sender":"带班老师"}

增加一个参数retrieve_recent_from保证服务器在收到新消息时直接返回最近的25条信息。工作原理是： 例：retrieve_recent_from=100 POST https://www.cocobabys.com/kindergarten/93740362/conversation/123456789?retrieve_recent_from=100 返回的结果为：返回服务器端包括最新创建的信息（假设编号为120）在内的，从id=101开始到id=120的信息，id从大到小排列，如果符合条件的信息超过25条只返回25条，因此可能新创建的信息不会返回。