Begin restructuring all Coursewares and Bonfires to one unified model and flow.

models/User.js

@@ -149,7 +149,8 @@ var userSchema = new mongoose.Schema({
   needsMigration: { type: Boolean, default: true },
   finishedWaypoints: { type: Boolean, default: false },
   sendMonthlyEmail: { type: Boolean, default: true },
-  challengesHash: {}
+  challengesHash: {},
+  currentChallenge: {}
 });
 
 /**