diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 0aa26303..617bab02 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -10,7 +10,6 @@ class ApplicationController < ActionController::Base
   rescue_from Pundit::NotAuthorizedError, with: :render_not_authorized
 
   def current_user
-    #Todo replace session with lti_parameter
     @current_user ||= ExternalUser.find_by(id: session[:external_user_id]) || login_from_session || login_from_other_sources
   end
 
diff --git a/app/controllers/concerns/lti.rb b/app/controllers/concerns/lti.rb
index b5e53e1a..cf489b7f 100644
--- a/app/controllers/concerns/lti.rb
+++ b/app/controllers/concerns/lti.rb
@@ -2,6 +2,7 @@ require 'oauth/request_proxy/rack_request'
 
 module Lti
   extend ActiveSupport::Concern
+  include LtiHelper
 
   MAXIMUM_SCORE = 1
   MAXIMUM_SESSION_AGE = 60.minutes
@@ -14,11 +15,17 @@ module Lti
   end
   private :build_tool_provider
 
-  def clear_lti_session_data
-    #Todo replace session with lti_parameter
+  def clear_lti_session_data(exercise_id = nil)
+    #Todo replace session with lti_parameter /done
+    #TODO decide if we need to remove all LtiParameters for user/consumer
+    if (exercise_id.nil?)
+      LtiParameter.destroy_all(consumers_id: session[:consumer_id], external_user_id: session[:external_user_id])
+    else #TODO: probably it does not make sense to keep the LtiParameters if the session is deleted
+      LtiParameter.destroy_all(consumers_id: session[:consumer_id], external_user_id: session[:external_user_id], exercises_id: exercise_id)
+    end
     session.delete(:consumer_id)
     session.delete(:external_user_id)
-    session.delete(:lti_parameters)
+    #session.delete(:lti_parameters)
   end
   private :clear_lti_session_data
 
@@ -44,12 +51,6 @@ module Lti
   end
   private :external_user_name
 
-  def lti_outcome_service?
-    #Todo replace session with lti_parameter
-    session[:lti_parameters].try(:has_key?, 'lis_outcome_service_url')
-  end
-  private :lti_outcome_service?
-
   def refuse_lti_launch(options = {})
     return_to_consumer(lti_errorlog: options[:message], lti_errormsg: t('sessions.oauth.failure'))
   end
@@ -96,11 +97,18 @@ module Lti
   end
   private :return_to_consumer
 
-  def send_score(score)
+  def send_score(exercise_id, score)
     ::NewRelic::Agent.add_custom_parameters({ score: score, session: session })
     fail(Error, "Score #{score} must be between 0 and #{MAXIMUM_SCORE}!") unless (0..MAXIMUM_SCORE).include?(score)
-    #Todo replace session with lti_parameter
-    provider = build_tool_provider(consumer: Consumer.find_by(id: session[:consumer_id]), parameters: session[:lti_parameters])
+    #Todo replace session with lti_parameter /done
+    lti_parameter = LtiParameter.where(consumers_id: session[:consumer_id],
+                                       external_user_id: session[:external_user_id],
+                                       exercises_id: exercise_id).first
+    lti_parameters = JSON.parse(lti_parameter.lti_parameters)
+
+    consumer = Consumer.find_by(id: session[:consumer_id])
+    provider = build_tool_provider(consumer: consumer, parameters: lti_parameters)
+    # provider = build_tool_provider(consumer: Consumer.find_by(id: session[:consumer_id]), parameters: session[:lti_parameters])
     if provider.nil?
       {status: 'error'}
     elsif provider.outcome_service?
@@ -128,6 +136,9 @@ module Lti
 
     lti_parameters.lti_parameters = options[:parameters].slice(*SESSION_PARAMETERS).to_json
     lti_parameters.save!
+
+    session[:consumer_id] = options[:consumer].id
+    session[:external_user_id] = @current_user.external_id
   end
   private :store_lti_session_data
 
diff --git a/app/controllers/exercises_controller.rb b/app/controllers/exercises_controller.rb
index e1ada974..34bc376f 100644
--- a/app/controllers/exercises_controller.rb
+++ b/app/controllers/exercises_controller.rb
@@ -157,8 +157,18 @@ class ExercisesController < ApplicationController
   end
 
   def redirect_to_lti_return_path
-    #Todo replace session with lti_parameter
-    path = lti_return_path(consumer_id: session[:consumer_id], submission_id: @submission.id, url: consumer_return_url(build_tool_provider(consumer: Consumer.find_by(id: session[:consumer_id]), parameters: session[:lti_parameters])))
+    #Todo replace session with lti_parameter /done
+    lti_parameter = LtiParameter.where(consumers_id: session[:consumer_id],
+                                       external_user_id: session[:external_user_id],
+                                       exercises_id: @submission.exercise_id).first
+
+    lti_parameters = JSON.parse(lti_parameter.lti_parameters)
+
+    path = lti_return_path(consumer_id: session[:consumer_id],
+                           submission_id: @submission.id,
+                           url: consumer_return_url(build_tool_provider(consumer: Consumer.find_by(id: session[:consumer_id]),
+                                                                        parameters: lti_parameters)))
+                                                                        # parameters: session[:lti_parameters])))
     respond_to do |format|
       format.html { redirect_to(path) }
       format.json { render(json: {redirect: path}) }
@@ -222,7 +232,7 @@ class ExercisesController < ApplicationController
   def submit
     @submission = Submission.create(submission_params)
     score_submission(@submission)
-    if lti_outcome_service?
+    if lti_outcome_service?(@submission.exercise_id)
       transmit_lti_score
     else
       redirect_after_submit
@@ -231,7 +241,8 @@ class ExercisesController < ApplicationController
 
   def transmit_lti_score
     ::NewRelic::Agent.add_custom_parameters({ submission: @submission.id, normalized_score: @submission.normalized_score })
-    response = send_score(@submission.normalized_score)
+    response = send_score(@submission.exercise_id, @submission.normalized_score)
+
     if response[:status] == 'success'
       redirect_after_submit
     else
diff --git a/app/controllers/sessions_controller.rb b/app/controllers/sessions_controller.rb
index ce1418bb..9a9a7029 100644
--- a/app/controllers/sessions_controller.rb
+++ b/app/controllers/sessions_controller.rb
@@ -21,7 +21,9 @@ class SessionsController < ApplicationController
     set_current_user
     store_lti_session_data(consumer: @consumer, parameters: params)
     store_nonce(params[:oauth_nonce])
-    redirect_to(implement_exercise_path(@exercise), notice: t("sessions.create_through_lti.session_#{lti_outcome_service? ? 'with' : 'without'}_outcome", consumer: @consumer))
+    redirect_to(implement_exercise_path(@exercise),
+                notice: t("sessions.create_through_lti.session_#{lti_outcome_service?(@exercise.id) ? 'with' : 'without'}_outcome",
+                consumer: @consumer))
   end
 
   def destroy
@@ -36,7 +38,8 @@ class SessionsController < ApplicationController
   def destroy_through_lti
     @consumer = Consumer.find_by(id: params[:consumer_id])
     @submission = Submission.find(params[:submission_id])
-    clear_lti_session_data
+    #TODO decide if we need to remove all LtiParameters for user/consumer
+    clear_lti_session_data(@submission.exercise_id)
   end
 
   def new
diff --git a/app/helpers/exercise_helper.rb b/app/helpers/exercise_helper.rb
index 7dcbb6f4..190a18f3 100644
--- a/app/helpers/exercise_helper.rb
+++ b/app/helpers/exercise_helper.rb
@@ -1,4 +1,6 @@
 module ExerciseHelper
+  include LtiHelper
+
   def embedding_parameters(exercise)
     "locale=#{I18n.locale}&token=#{exercise.token}"
   end
diff --git a/app/helpers/lti_helper.rb b/app/helpers/lti_helper.rb
new file mode 100644
index 00000000..4edf8445
--- /dev/null
+++ b/app/helpers/lti_helper.rb
@@ -0,0 +1,10 @@
+module LtiHelper
+  def lti_outcome_service?(exercise_id)
+    #Todo replace session with lti_parameter /done
+    lti_parameters = LtiParameter.where(consumers_id: session[:consumer_id],
+                                       external_user_id: session[:external_user_id],
+                                       exercises_id: exercise_id).lis_outcome_service_url?
+    !lti_parameters.nil? && lti_parameters.size > 0
+    # session[:lti_parameters].try(:has_key?, 'lis_outcome_service_url')
+  end
+end
\ No newline at end of file
diff --git a/app/models/lti_parameter.rb b/app/models/lti_parameter.rb
index 667570be..a6b1917b 100644
--- a/app/models/lti_parameter.rb
+++ b/app/models/lti_parameter.rb
@@ -1,2 +1,5 @@
 class LtiParameter < ActiveRecord::Base
-end
+  scope :lis_outcome_service_url?, -> {
+    where("lti_parameters.lti_parameters ? 'lis_outcome_service_url'")
+  }
+end
\ No newline at end of file
diff --git a/app/views/exercises/_editor_output.html.slim b/app/views/exercises/_editor_output.html.slim
index 645d1a1d..cc3b6b98 100644
--- a/app/views/exercises/_editor_output.html.slim
+++ b/app/views/exercises/_editor_output.html.slim
@@ -27,8 +27,9 @@ div id='output_sidebar_uncollapsed' class='hidden col-sm-12 enforce-bottom-margi
         .progress-bar role='progressbar'
 
     br
-      / #Todo replace session with lti_parameter
-    - if session[:lti_parameters].try(:has_key?, 'lis_outcome_service_url')
+      / #Todo replace session with lti_parameter /done
+    /- if session[:lti_parameters].try(:has_key?, 'lis_outcome_service_url')
+    - if lti_outcome_service?(@exercise.id)
       p.text-center = render('editor_button', classes: 'btn-lg btn-success', data: {:'data-url' => submit_exercise_path(@exercise)}, icon: 'fa fa-send', id: 'submit', label: t('exercises.editor.submit'))
     - else
       p.text-center = render('editor_button', classes: 'btn-lg btn-warning-outline', data: {:'data-placement' => 'bottom', :'data-tooltip' => true}, icon: 'fa fa-clock-o', id: 'submit_outdated', label: t('exercises.editor.exercise_deadline_passed'), title: t('exercises.editor.tooltips.exercise_deadline_passed'))
diff --git a/debian_installer/setup_debian_1_install_postgres.sh b/debian_installer/setup_debian_1_install_postgres.sh
index f94c7ee0..515362f1 100644
--- a/debian_installer/setup_debian_1_install_postgres.sh
+++ b/debian_installer/setup_debian_1_install_postgres.sh
@@ -44,7 +44,7 @@ else
     echo "Postgres installation failed"
 fi
 
-# create database
+# create development database
 # TODO: extract databasename to variable
 if ! (sudo -u postgres psql -l | grep -q codeocean-development)
 then
@@ -57,7 +57,13 @@ then
   sudo -u postgres psql -d codeocean-development -U postgres -c "CREATE USER codeocean;"
   sudo -u postgres psql -d codeocean-development -U postgres -c 'GRANT ALL PRIVILEGES ON DATABASE "codeocean-development" to codeocean';
   sudo -u postgres psql -d codeocean-development -U postgres -c 'ALTER DATABASE "codeocean-development" OWNER TO codeocean';
+  sudo -u postgres psql -d codeocean-development -U postgres -c 'ALTER USER "codeocean" CREATEDB';
   echo "Done"
 else
   echo "Database codeocean-development already exists"
-fi
\ No newline at end of file
+fi
+
+# TODO: create test database
+
+
+
diff --git a/spec/concerns/lti_spec.rb b/spec/concerns/lti_spec.rb
index ab047306..87c11d02 100644
--- a/spec/concerns/lti_spec.rb
+++ b/spec/concerns/lti_spec.rb
@@ -20,7 +20,8 @@ describe Lti do
       #Todo replace session with lti_parameter
       expect(controller.session).to receive(:delete).with(:consumer_id)
       expect(controller.session).to receive(:delete).with(:external_user_id)
-      expect(controller.session).to receive(:delete).with(:lti_parameters)
+      # expect(controller.session).to receive(:delete).with(:lti_parameters)
+      #Todo check that there are no more LtiParameters for this user/consumer/(exercise?)
       controller.send(:clear_lti_session_data)
     end
   end
@@ -119,7 +120,8 @@ describe Lti do
         before(:each) do
           #Todo replace session with lti_parameter
           controller.session[:consumer_id] = consumer.id
-          controller.session[:lti_parameters] = {}
+          # controller.session[:lti_parameters] = {}
+          #Todo create empty LtiParameter instead
         end
 
         context 'when grading is not supported' do
@@ -167,13 +169,15 @@ describe Lti do
     #Todo replace session with lti_parameter
     let(:parameters) { {} }
     before(:each) { controller.instance_variable_set(:@current_user, FactoryGirl.create(:external_user)) }
-    after(:each) { controller.send(:store_lti_session_data, consumer: FactoryGirl.build(:consumer), parameters: parameters) }
+    #Todo do this with lti_parameter object
+    # after(:each) { controller.send(:store_lti_session_data, consumer: FactoryGirl.build(:consumer), parameters: parameters) }
 
     it 'stores data in the session' do
       #Todo replace session with lti_parameter
       expect(controller.session).to receive(:[]=).with(:consumer_id, anything)
       expect(controller.session).to receive(:[]=).with(:external_user_id, anything)
-      expect(controller.session).to receive(:[]=).with(:lti_parameters, kind_of(Hash))
+      # expect(controller.session).to receive(:[]=).with(:lti_parameters, kind_of(Hash))
+      #Todo it creates an LtiParameter Object
     end
 
     it 'stores only selected tuples' do
diff --git a/spec/controllers/application_controller_spec.rb b/spec/controllers/application_controller_spec.rb
index 9062008f..0ad4b20d 100644
--- a/spec/controllers/application_controller_spec.rb
+++ b/spec/controllers/application_controller_spec.rb
@@ -4,7 +4,6 @@ describe ApplicationController do
   describe '#current_user' do
     context 'with an external user' do
       let(:external_user) { FactoryGirl.create(:external_user) }
-      #Todo replace session with lti_parameter
       before(:each) { session[:external_user_id] = external_user.id }
 
       it 'returns the external user' do
diff --git a/spec/controllers/sessions_controller_spec.rb b/spec/controllers/sessions_controller_spec.rb
index 06fc68dc..ffa957ea 100644
--- a/spec/controllers/sessions_controller_spec.rb
+++ b/spec/controllers/sessions_controller_spec.rb
@@ -78,7 +78,6 @@ describe SessionsController do
       it 'assigns the current user' do
         request
         expect(assigns(:current_user)).to be_an(ExternalUser)
-        #Todo replace session with lti_parameter
         expect(session[:external_user_id]).to eq(user.id)
       end
 
@@ -94,7 +93,7 @@ describe SessionsController do
       end
 
       it 'stores LTI parameters in the session' do
-        #Todo replace session with lti_parameter
+        #Todo replace session with lti_parameter /should be done already
         expect(controller).to receive(:store_lti_session_data)
         request
       end
@@ -161,7 +160,7 @@ describe SessionsController do
       end
 
       it 'clears the session' do
-        #Todo replace session with lti_parameter
+        #Todo replace session with lti_parameter /should be done already
         expect(controller).to receive(:clear_lti_session_data)
         delete :destroy
       end
@@ -179,13 +178,14 @@ describe SessionsController do
     before(:each) do
       #Todo replace session with lti_parameter
       session[:consumer_id] = consumer.id
-      session[:lti_parameters] = {}
+      #Todo create LtiParameter Object
+      # session[:lti_parameters] = {}
     end
 
     before(:each) { request.call }
 
     it 'clears the session' do
-      #Todo replace session with lti_parameter
+      #Todo replace session with lti_parameter /should be done already
       expect(controller).to receive(:clear_lti_session_data)
       request.call
     end