Use invoke instead of fabric, for release task

tasks.py

@@ -0,0 +1,36 @@
+# -*- coding: utf-8; -*-
+################################################################################
+#
+#  sqlalchemy-pervasive -- SQLAlchemy Dialect for Pervasive PSQL
+#  Copyright © 2013-2018 Sacramento Natural Foods Co-op, Inc
+#
+#  This file is part of sqlalchemy-pervasive.
+#
+#  sqlalchemy-pervasive is free software: you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License as published by the
+#  Free Software Foundation, either version 3 of the License, or (at your
+#  option) any later version.
+#
+#  sqlalchemy-pervasive is distributed in the hope that it will be useful, but
+#  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+#  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+#  more details.
+#
+#  You should have received a copy of the GNU General Public License along with
+#  sqlalchemy-pervasive.  If not, see <http://www.gnu.org/licenses/>.
+#
+################################################################################
+
+from __future__ import unicode_literals, absolute_import
+
+import shutil
+from invoke import task
+
+
+@task
+def release(ctx):
+    """
+    Release a new version of 'sqlalchemy-pervasive'.
+    """
+    shutil.rmtree('sqlalchemy_pervasive.egg-info')
+    ctx.run('python setup.py sdist --formats=gztar upload')