Error appear when current_user is active.

View (pages/index):

<% if current_user %>
Signed in as <%= current_user.name %>!
<%= link_to 'Sign out', signout_path %>
<% end %>

Application controller:

class ApplicationController < ActionController::Base

1. Prevent CSRF attacks by raising an exception.
2. For APIs, you may want to use :null_session instead.
   protect_from_forgery with: :exception

private

def current_user
@current_user ||= User.find(session[:user_id]) if session[:user_id]
end

helper_method :current_user
end

User model:

class User
include Mongoid::Document
include Mongoid::Timestamps

field :provider, type: String
field :uid, type: String
field :name, type: String

def self.from_omniauth(auth)
where(auth.slice("provider", "uid")).first || create_from_omniauth(auth)
end

def self.create_from_omniauth(auth)
create! do |user|
user.provider = auth["provider"]
user.uid = auth["uid"]
user.name = auth["extra"]["raw_info"]["name"]
end
end
end

Error:

The operation: #<Moped::Protocol::Query
@length=90
@request_id=19
@response_to=0
@op_code=2004
@flags=[]
@full_collection_name="monkeywork_development.users"
@skip=0
@limit=0
@selector={"_id"=>{"$oid"=>BSON::ObjectId('54e5d31c5365623549000000')}}
@fields=nil>
failed with error 17287: "Can't canonicalize query: BadValue unknown operator: $oid"