Implement a basic friend chat

Objective Implement a simple chat system for an individual user to send and receive messages with another.

Requirements stack

[x] Include firebase rules for chats to secure data.
[x] Set an index of tabs to tab Chats when a user joins the chat room.
[x] Allow a user to be accessed a chat room by clicking a Chat button from friend's profile.
[x] A new chat room is allowed to be created by entire users in the friend list, without acquiring a permit from another user.
[x] A chat room must be placed in both users Chats page, only if the user sends at least one message to another.
[x] The last message of the chat room should be described on the list as a history of each conversation item.
[x] Display arrival time of messages.
[x] Chat messages must be intuitively distinguishable form sender and receiver.
[x] Allow users to use emoji during a chat.
[x] Identify members in a chat room by displaying a profile picture along with either display name or username.

jeffminsungkim / Ashy