diff --git a/NEWS.mdtext b/NEWS.mdtext
index 7205df9..9f62604 100644
--- a/NEWS.mdtext
+++ b/NEWS.mdtext
@@ -2,15 +2,17 @@
 
 ## Bugfixes
 
-- If an anonymous or authenticated user had no access
-  to any project in a forge, all projects were listed
-  for him (but still no one was actually accessible).
-  This has been fixed. 
-
-- Fixed a problem where the SyncGit plugin doesn't properly
-  updates the authorized_keys file when the public key
-  data contained slashes (thanks to Simon Gareste for the
-  fix!)
+- If an anonymous or authenticated user had no access to any project in a 
+  forge, all projects were listed for him (but still no one was actually
+  accessible). This has been fixed. 
+
+- Fixed a problem where the SyncGit plugin doesn't properly updates the
+  authorized_keys file when the public key data contained slashes (thanks
+  to Simon Gareste for the fix!)
+
+- Under PostgreSQL new projects could not be created due to a failing
+  foreign key relation. Adding project tags was not possible for a similar
+  reason. This has been fixed (issue 800, continued).
 
 # InDefero 1.3.2 - Wed May 09 20:05 2012 UTC
 
diff --git a/src/IDF/Migrations/25NullableProjectInTag.php b/src/IDF/Migrations/25NullableProjectInTag.php
index 22e10d7..0829acf 100644
--- a/src/IDF/Migrations/25NullableProjectInTag.php
+++ b/src/IDF/Migrations/25NullableProjectInTag.php
@@ -37,6 +37,7 @@ function IDF_Migrations_25NullableProjectInTag_up($params=null)
 
 function IDF_Migrations_25NullableProjectInTag_down($params=null)
 {
+    $engine = Pluf::f('db_engine');
     $db = Pluf::db();
     if ($engine === 'PostgreSQL') {
         $db->execute('ALTER TABLE '.$db->pfx.'idf_tags ALTER COLUMN project SET NOT NULL');
diff --git a/src/IDF/Migrations/26NullableActivityInProject.php b/src/IDF/Migrations/26NullableActivityInProject.php
new file mode 100644
index 0000000..6335d84
--- /dev/null
+++ b/src/IDF/Migrations/26NullableActivityInProject.php
@@ -0,0 +1,46 @@
+<?php
+/* -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+# ***** BEGIN LICENSE BLOCK *****
+# This file is part of InDefero, an open source project management application.
+# Copyright (C) 2008-2012 Céondo Ltd and contributors.
+#
+# InDefero is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# InDefero is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+#
+# ***** END LICENSE BLOCK ***** */
+
+function IDF_Migrations_26NullableActivityInProject_up($params=null)
+{
+    $engine = Pluf::f('db_engine');
+    $db = Pluf::db();
+    if ($engine === 'PostgreSQL') {
+        $db->execute('ALTER TABLE '.$db->pfx.'idf_projects ALTER COLUMN current_activity DROP NOT NULL');
+    } else if ($engine === 'MySQL') {
+        $db->execute('ALTER TABLE '.$db->pfx.'idf_projects MODIFY current_activity MEDIUMINT NULL');
+        // this is only needed for non-transactional setups where MySQL set 0 as default value
+        $db->execute('UPDATE '.$db->pfx.'idf_projects SET current_activity=NULL WHERE current_activity=0');
+    }
+}
+
+function IDF_Migrations_26NullableActivityInProject_down($params=null)
+{
+    $engine = Pluf::f('db_engine');
+    $db = Pluf::db();
+    if ($engine === 'PostgreSQL') {
+        $db->execute('ALTER TABLE '.$db->pfx.'idf_projects ALTER COLUMN current_activity SET NOT NULL');
+    } else if ($engine === 'MySQL') {
+        $db->execute('ALTER TABLE '.$db->pfx.'idf_projects MODIFY current_activity MEDIUMINT NOT NULL');
+    }
+}
diff --git a/src/IDF/Project.php b/src/IDF/Project.php
index 04cd41b..b773281 100644
--- a/src/IDF/Project.php
+++ b/src/IDF/Project.php
@@ -105,6 +105,8 @@ class IDF_Project extends Pluf_Model
                                   'type' => 'Pluf_DB_Field_Foreignkey',
                                   'model' => 'IDF_ProjectActivity',
                                   'blank' => true,
+                                  'is_null' => true,
+                                  'default' => null,
                                   'verbose' => __('current project activity'),
                                   ),
                             );
diff --git a/src/IDF/Tag.php b/src/IDF/Tag.php
index 7b6349e..6809bc2 100644
--- a/src/IDF/Tag.php
+++ b/src/IDF/Tag.php
@@ -50,6 +50,7 @@ class IDF_Tag extends Pluf_Model
                                   'model' => 'IDF_Project',
                                   'blank' => true,
                                   'is_null' => true,
+                                  'default' => null,
                                   'verbose' => __('project'),
                                   ),
                             'class' =>