Add custom DatabaseWarning

This warning is used to categorize the SQLite production usage
warning.

Signed-off-by: Roberto Rosario <Roberto.Rosario@mayan-edms.com>

mayan/apps/common/apps.py

@@ -41,6 +41,7 @@ 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__)
 
@@ -88,7 +89,9 @@ 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='menu_main', template_name='appearance/menu_main.html'

mayan/apps/common/warnings.py

@@ -1,6 +1,12 @@
 from __future__ import absolute_import
 
 
+class DatabaseWarning(UserWarning):
+    """
+    Warning when using unsupported database backends
+    """
+
+
 class InterfaceWarning(UserWarning):
     """
     Warning when using obsolete internal interfaces