diff --git a/MIGRATION b/MIGRATION
new file mode 100644
index 0000000..14f37a7
--- /dev/null
+++ b/MIGRATION
@@ -0,0 +1,51 @@
+=================
+Migration Details 
+=================
+
+Version 0.3
+===========
+
+1. SQL to move party_address to nereid_user
+-------------------------------------------
+
+Address which was used for login was migrated to nereid_user. To
+retain the existing users and their IDs (used in sessions) the
+users data needs to be migrated from party.address to nereid.user
+
+SQL::
+
+INSERT INTO nereid_user 
+SELECT 
+	"address"."id" AS id,
+	"address"."create_date" AS create_date, 
+	"address"."write_date" AS write_date, 
+	"address"."create_uid" AS create_uid, 
+	"address"."write_uid" AS write_uid, 
+	"party"."company" AS company,
+	"address"."party" AS party,
+	"address"."activation_code" AS activation_code,
+	"address"."salt" AS salt,
+	"contact_mechanism"."value" AS email,
+	"address"."password" AS password
+FROM party_address AS address
+JOIN party_party AS party ON party.id = address.party
+LEFT JOIN party_contact_mechanism AS contact_mechanism ON contact_mechanism.id = address.email
+WHERE 
+	"address"."email" IS NOT NULL 
+    AND "address"."password" IS NOT NULL 
+    AND "party"."company" IS NOT NULL;
+
+
+2. Application Settings
+-----------------------
+
+`TRYTON_USER` and `GUEST_USER` which were application config parameters in
+previous version are now part of `nereid.website` settings. This avoids
+looking up IDs of these records from  database to then build the app settings.
+
+This affects two places:
+
+  1. Application settings in launchers: `TRYTON_USER` and `GUEST_USER` needs
+     not be specified anymore.
+  2. Unit Tests: `application_user` (eqv. of `TRYTON_USER`) and `guest_user`
+     are not 
diff --git a/nereid/application.py b/nereid/application.py
index 7b534cf..f9934b6 100644
--- a/nereid/application.py
+++ b/nereid/application.py
@@ -241,7 +241,7 @@ class Nereid(BackendMixin, RoutingMixin,
         self._before_request_lock = Lock()
 
         _PackageBoundObject.__init__(self, __name__)
-        BackendMixin.__init__(self, **config) 
+        BackendMixin.__init__(self, **config)
         RoutingMixin.__init__(self, **config)
         CacheMixin.__init__(self, **config)
         TemplateMixin.__init__(self, **config)
diff --git a/nereid/backend.py b/nereid/backend.py
index ea602bc..c157bbc 100644
--- a/nereid/backend.py
+++ b/nereid/backend.py
@@ -40,6 +40,13 @@ class BackendMixin(object):
     #: Configuration file for Tryton
     tryton_configfile = ConfigAttribute('TRYTON_CONFIG')
     database_name = ConfigAttribute('DATABASE_NAME')
+
+    #: This attribute was previously used to specify ID of the res.user
+    #: that nereid should be using to connect to Tryton. This attribute
+    #: is now set during the initialisation of the class. If any attribute
+    #: is set in the config settings, they are ignored
+    #: 
+    #: ..versionchanged:0.3
     tryton_user = ConfigAttribute('TRYTON_USER')
     tryton_context = ConfigAttribute('TRYTON_CONTEXT')
 
@@ -48,6 +55,26 @@ class BackendMixin(object):
             from trytond.config import CONFIG
             CONFIG.configfile = self.tryton_configfile
             CONFIG.load()
+        with self.root_transaction:
+            website_obj = self.pool.get('nereid.website')
+            user_obj = self.pool.get('res.user')
+
+            # Find the application_user and guest_user
+            website_id, = website_obj.search([
+                ('name', '=', self.site)
+            ])
+            website = website_obj.browse(website_id)
+            self.tryton_user = website.application_user.id
+            self.guest_user = website.guest_user.id
+
+            # Update the Tryton context
+            if not self.tryton_context:
+                self.tryton_context = {}
+            new_context = user_obj._get_preferences(
+                website.application_user, context_only=True
+            )
+            self.tryton_context.update(new_context)
+
 
     def load_connection(self):
         "Actual loading of connection takes place here"
@@ -81,7 +108,7 @@ class BackendMixin(object):
 
     @property
     def transaction(self):
-        """Allows the use of the transaction as a context manager. 
+        """Allows the use of the transaction as a context manager.
 
         Example::
 
@@ -93,6 +120,15 @@ class BackendMixin(object):
         return TransactionManager(
             self.database_name, self.tryton_user, self.tryton_context)
 
+    @property
+    def root_transaction(self):
+        """Allows the use of the transaction as a context manager with the
+        root user.
+
+        .. versionadded::0.3
+        """
+        return TransactionManager(self.database_name, 0, self.tryton_context)
+
     def get_method(self, model_method):
         """Get the object from pool and fetch the method from it
 
diff --git a/nereid/testing.py b/nereid/testing.py
index a3c5144..f6fa227 100644
--- a/nereid/testing.py
+++ b/nereid/testing.py
@@ -285,6 +285,9 @@ def create_site(obj, name, url_map=None, company=None, **options):
         options['default_language'], = lang_obj.search(
             [('code', '=', 'en_US')])
 
+    if 'application_user' not in options:
+        options['application_user'] = 1
+
     return site_obj.create(options)