Move chat to own module.

src/modules/chat.js

@@ -0,0 +1,33 @@
+const chat = {
+  state: {
+    messages: [],
+    channel: null
+  },
+  mutations: {
+    setChannel (state, channel) {
+      state.channel = channel
+    },
+    addMessage (state, message) {
+      state.messages.push(message)
+      state.messages = state.messages.slice(-19, 20)
+    },
+    setMessages (state, messages) {
+      state.messages = messages.slice(-19, 20)
+    }
+  },
+  actions: {
+    initializeChat (store, socket) {
+      const channel = socket.channel('chat:public')
+      channel.on('new_msg', (msg) => {
+        store.commit('addMessage', msg)
+      })
+      channel.on('messages', ({messages}) => {
+        store.commit('setMessages', messages)
+      })
+      channel.join()
+      store.commit('setChannel', channel)
+    }
+  }
+}
+
+export default chat