realtime: Create extensions in alembic ast-db-manage contribution

When the alembic scripts were written for creating Asterisk
realtime databases the extensions table for dialplan wasn't
included.  This update creates the extensions table.

(closes issue ASTERISK-22815)
Reported by: Zone Conkle
Review: https://reviewboard.asterisk.org/r/3064/
........

Merged revisions 403713 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@403714 65c4cc65-6c06-0410-ace0-fbb531ad65f3

contrib/ast-db-manage/config/versions/581a4264e537_adding_extensions.py

@@ -0,0 +1,50 @@
+#
+# Asterisk -- An open source telephony toolkit.
+#
+# Copyright (C) 2013, Digium, Inc.
+#
+# Scott Griepentrog <sgriepentrog@digium.com>
+#
+# See http://www.asterisk.org for more information about
+# the Asterisk project. Please do not directly contact
+# any of the maintainers of this project for assistance;
+# the project provides a web site, mailing lists and IRC
+# channels for your use.
+#
+# This program is free software, distributed under the terms of
+# the GNU General Public License Version 2. See the LICENSE file
+# at the top of the source tree.
+#
+
+"""adding extensions
+
+Revision ID: 581a4264e537
+Revises: 43956d550a44
+Create Date: 2013-12-10 16:32:41.145327
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '581a4264e537'
+down_revision = '43956d550a44'
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade():
+    op.create_table(
+        'extensions',
+        sa.Column('id', sa.BigInteger, nullable=False, unique=True,
+                  autoincrement=True),
+        sa.Column('context', sa.String(40), primary_key=True, nullable=False),
+        sa.Column('exten', sa.String(40), primary_key=True, nullable=False),
+        sa.Column('priority', sa.Integer, primary_key=True, nullable=False,
+                  autoincrement=True),
+        sa.Column('app', sa.String(40), nullable=False),
+        sa.Column('appdata', sa.String(256), nullable=False),
+    )
+
+
+def downgrade():
+    op.drop_table('extensions')