// Handles the post request for following a user
router.post('/follow-user', function(req, res, next) {

  // First, find the user from the user page being viewed
  User.findOne({ username: req.body.username }, function(err, user) {

    // Add to users followers with ID of the logged in user
    user.followers = req.user._id;

    // Create variable for user from page being viewed
    var followedUser = user._id;

    // Save followers data to user
    user.save();

    // Secondly, find the user account for the logged in user
    User.findOne({ username: req.user.username }, function(err, user) {

      // Add the user ID from the users profile the follow button was clicked
      user.following = followedUser;

      // Save following data to user
      user.save();
    });
  });
});

var userSchema = new Schema({
  username: { type: String, required: true, unique: true },
  password: { type: String, required: true },
  email: { type: String, required: true },
  avatar: { type: String },
  bio: { type: String },
  following: [{ type: Schema.ObjectId, ref: 'User' }],
  followers: [{ type: Schema.ObjectId, ref: 'User' }],
});

User.findOne({ username: req.body.username }, function(err, user) {

    user.followers.push(req.user._id);
    var followedUser = user._id;
    user.save(function(err){
        if(err){
            //Handle error
            //send error response
        }
        else
        {
            // Secondly, find the user account for the logged in user
            User.findOne({ username: req.user.username }, function(err, user) {

                user.following.push(followedUser);
                user.save(function(err){
                    if(err){
                        //Handle error
                        //send error response
                    }
                    else{
                        //send success response
                    }
                });
            });
        }
    });
});

{
                    //Handle error
                    //send error response
                }
                else{
                    //send success response
                }
            });