Add some comments

bot/facebook/index.js

@@ -14,6 +14,12 @@ const fbTemplate = require('claudia-bot-builder/lib/facebook/format-message')
  */
 const recipients = []
 
+/**
+ * GET webhook
+ *
+ * Gets executed when you add the Webhook URL to the Facebook and it tries
+ * to validate it.
+ */
 const verifyToken = req => {
   if (req.query['hub.verify_token'] === process.env.FB_VERIFY_TOKEN) {
     return req.query['hub.challenge']
@@ -26,6 +32,9 @@ const verifyToken = req => {
   return 'INVALID TOKEN'
 }
 
+/**
+ * Validate and convert request to a common message format
+ */
 const fbMessage = async req => {
   req.env = {facebookAppSecret: process.env.FB_APP_SECRET}
   req.rawBody = await text(req)
@@ -39,6 +48,11 @@ const fbMessage = async req => {
   return isValid ? message : false
 }
 
+/**
+ * POST webhook
+ *
+ * Gets executed on any message to the Bot.
+ */
 const respond = async (req, res) => {
   const message = await fbMessage(req)
   if (message) {