add libchat

libchat/README.md

@@ -0,0 +1,19 @@
+
+# A Universal Chat History Management
+
+## Fields
+
+Table Message:
++ source(enum): can be 0:wechat, ...
++ time(time)
++ sender: id of the sender. id follows the name convention of source
++ chatroom: id of the chatroom (can be a private chat with a sender, or a group chat)
++ text: text content. emojis are encoded according to the source
++ image: binary of the image.
++ sound: binary of an audio
++ extra_data: other possible data specific to the source.
+
+Table Wechat:
++ avatars
++ nicknames
++ emojis