astakos: Introduce base projects

Every user is associated with a special-purpose `base' project. Its
mission is to manage the user's base quota.

snf-astakos-app/astakos/im/models.py

@@ -469,6 +469,10 @@ class AstakosUser(User):
     disturbed_quota = models.BooleanField(_('Needs quotaholder syncing'),
                                           default=False, db_index=True)
 
+    # This could have been OneToOneField, but fails due to
+    # https://code.djangoproject.com/ticket/13781 (fixed in v1.6)
+    base_project = models.ForeignKey('Project', related_name="base_user")
+
     objects = AstakosUserManager()
 
     @property
@@ -1596,6 +1600,7 @@ class Project(models.Model):
         blank=True,
         through='ProjectResourceQuota')
     private = models.BooleanField(default=False)
+    is_base = models.BooleanField(default=False)
 
     objects = ProjectManager()