Facebook Auth log out with Rails and Parse - ruby-on-rails

Question

I am having trouble finding a way to log out from facebook. We are logging in using window.location = '/auth/facebook' which redirects the user to a facebook login page, and calls a callback route /auth/facebook/callback(declared in developers.facebook.com) to a method in my session_controller/create.
The session_controller/create method looks like this
def create
#get auth hash from omniauth
auth = auth_hash
#data = {}
#session_data = {}
#data['id'] = auth['uid']
#data['access_token'] = auth['credentials']['token']
#time must be in iso format, see parse rest api for details under linking
#expiry = Time.at(auth['credentials']['expires_at']).iso8601
#data['expiration_date'] = #expiry
#create new linking user object
user = Parse::User::Facebook.new(#data)
# add other user information to body of PARSE::USER::FACEBOOK instance
user.body['email'] = auth['info']['email']
user.body['auth'] = true
user.body['fullname'] = auth['info']['name']
user.body['ip'] = request.remote_ip
user.body['image'] = auth['info']['image'] if auth['info']['image']
user.body['admin'] = false
user.body['facebookId'] = auth['uid']
user.body['facebookToken'] = auth['credentials']['token']
user.body['has_seen_web_tutorial'] = false
#current_user = user.save
#save necessary session information
session['name'] = #current_user['fullname']
session['points'] = #current_user['points']
session['objectId'] = #current_user['objectId']
session['sessionToken'] = #current_user['sessionToken']
session['image'] = #current_user['image']
session['location'] = #current_user['location']
#session_data['name'] = session['name']
#session_data['fullname'] = #current_user['fullname']
#session_data['points'] = session['points']
#session_data['objectId'] = session['objectId']
#session_data['image'] = session['image']
if auth['info']['image']
File.open('temp_face.png', 'wb') do |file|
file << open(auth['info']['image'], :allow_redirections => :safe).read
end
photo = Parse::File.new({
:body => IO.read("temp_face.png"),
:local_filename => "temp_face.png",
:content_type => "image/png"
})
photo.save
#user.body['image'] = photo
end
image = Parse::Object.new("ImageUploads")
image['fileKey'] = photo
image['owner'] = Parse::Pointer.new({"className" => "_User", "objectId" => session['objectId']})
image['type'] = 'profile'
#image['location']
saved_image = image.save
redirect_to listing_index_path
end
I am having trouble trying to log out. Very new to rails. Any help please?
Thank you