Add DatabaseWarning to tag SQLite use warning

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

HISTORY.rst

@@ -9,6 +9,7 @@
 * Switch to full app paths.
 * Split document app models into separate modules.
 * Split workflow views into separate modules.
+* Add custom DatabaseWarning to tag the SQLite usage warning.
 
 3.1.11 (2019-04-XX)
 ===================

mayan/apps/common/apps.py

@@ -42,6 +42,7 @@ from .settings import (
 from .signals import pre_initial_setup, pre_upgrade
 from .tasks import task_delete_stale_uploads  # NOQA - Force task registration
 from .utils import check_for_sqlite
+from .warnings import DatabaseWarning
 
 logger = logging.getLogger(__name__)
 
@@ -89,7 +90,9 @@ class CommonApp(MayanAppConfig):
     def ready(self):
         super(CommonApp, self).ready()
         if check_for_sqlite():
-            warnings.warn(force_text(MESSAGE_SQLITE_WARNING))
+            warnings.warn(
+                category=DatabaseWarning, message=force_text(MESSAGE_SQLITE_WARNING)
+            )
 
         Template(
             name='main_menu', template_name='appearance/main_menu.html'

mayan/apps/common/warnings.py

@@ -0,0 +1,7 @@
+from __future__ import absolute_import
+
+
+class DatabaseWarning(UserWarning):
+    """
+    Warning when using unsupported database backends
+    """