Add deprecation warning to convertdb

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

HISTORY.rst

@@ -240,6 +240,7 @@
 * Remove MultipleInstanceActionMixin.
 * Backport MultipleObjectMixin improvements.
 * Remove ObjectListPermissionFilterMixin.
+* Add deprecation warning to convertdb 
 
 3.1.11 (2019-04-XX)
 ===================

docs/releases/3.2.rst

@@ -273,6 +273,7 @@ Other changes
 * Remove MultipleInstanceActionMixin.
 * Backport MultipleObjectMixin improvements.
 * Remove ObjectListPermissionFilterMixin.
+* Add deprecation warning to convertdb 
 
 Removals
 --------

mayan/apps/common/literals.py

@@ -6,6 +6,9 @@ DEFAULT_COMMON_HOME_VIEW = 'common:home'
 DELETE_STALE_UPLOADS_INTERVAL = 60 * 10  # 10 minutes
 DJANGO_SQLITE_BACKEND = 'django.db.backends.sqlite3'
 
+MESSAGE_DEPRECATION_WARNING = _(
+    'This feature has been deprecated and will be removed in a future version.'
+)
 MESSAGE_SQLITE_WARNING = _(
     'Your database backend is set to use SQLite. SQLite should only be used '
     'for development and testing, not for production.'

mayan/apps/common/management/commands/convertdb.py

@@ -2,6 +2,7 @@ from __future__ import unicode_literals
 
 import errno
 import os
+import warnings
 
 from pathlib2 import Path
 
@@ -14,6 +15,9 @@ from django.utils.translation import ugettext_lazy as _
 from mayan.apps.documents.models import DocumentType
 from mayan.apps.storage.utils import fs_cleanup
 
+from ...literals import MESSAGE_DEPRECATION_WARNING
+from ...warnings import DeprecationWarning
+
 CONVERTDB_FOLDER = 'convertdb'
 CONVERTDB_OUTPUT_FILENAME = 'migrate.json'
 
@@ -21,6 +25,14 @@ CONVERTDB_OUTPUT_FILENAME = 'migrate.json'
 class Command(management.BaseCommand):
     help = 'Convert from a database backend to another one.'
 
+    def __init__(self, *args, **kwargs):
+        warnings.warn(
+            category=DeprecationWarning,
+            message=force_text(MESSAGE_DEPRECATION_WARNING)
+        )
+
+        super(Command, self).__init__(*args, **kwargs)
+
     def add_arguments(self, parser):
         parser.add_argument(
             'args', metavar='app_label[.ModelName]', nargs='*',

mayan/apps/common/warnings.py

@@ -7,6 +7,12 @@ class DatabaseWarning(UserWarning):
     """
 
 
+class DeprecationWarning(UserWarning):
+    """
+    Warning when a feature or interface has been deprecated
+    """
+
+
 class InterfaceWarning(UserWarning):
     """
     Warning when using obsolete internal interfaces