db: add Alembic "migration environment"

Add in kallithea/alembic an unmodified Alembic "migration environment",
as generated by 'alembic init':

Copyright (C) 2009-2016 by Michael Bayer.
Alembic is a trademark of Michael Bayer.

Also update LICENSE, MANIFEST and setup metadata.

kallithea/alembic/env.py

@@ -0,0 +1,70 b''
+from __future__ import with_statement
+from alembic import context
+from sqlalchemy import engine_from_config, pool
+from logging.config import fileConfig
+
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+
+# Interpret the config file for Python logging.
+# This line sets up loggers basically.
+fileConfig(config.config_file_name)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+# from myapp import mymodel
+# target_metadata = mymodel.Base.metadata
+target_metadata = None
+
+# other values from the config, defined by the needs of env.py,
+# can be acquired:
+# my_important_option = config.get_main_option("my_important_option")
+# ... etc.
+
+
+def run_migrations_offline():
+    """Run migrations in 'offline' mode.
+
+    This configures the context with just a URL
+    and not an Engine, though an Engine is acceptable
+    here as well.  By skipping the Engine creation
+    we don't even need a DBAPI to be available.
+
+    Calls to context.execute() here emit the given string to the
+    script output.
+
+    """
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url, target_metadata=target_metadata, literal_binds=True)
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online():
+    """Run migrations in 'online' mode.
+
+    In this scenario we need to create an Engine
+    and associate a connection with the context.
+
+    """
+    connectable = engine_from_config(
+        config.get_section(config.config_ini_section),
+        prefix='sqlalchemy.',
+        poolclass=pool.NullPool)
+
+    with connectable.connect() as connection:
+        context.configure(
+            connection=connection,
+            target_metadata=target_metadata
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

kallithea/alembic/script.py.mako

@@ -0,0 +1,24 b''
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = ${repr(up_revision)}
+down_revision = ${repr(down_revision)}
+branch_labels = ${repr(branch_labels)}
+depends_on = ${repr(depends_on)}
+
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+def upgrade():
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade():
+    ${downgrades if downgrades else "pass"}

LICENSE.md

@@ -22,6 +22,18 b' Various third-party code under GPLv3-com'
 of Kallithea.
 
 
+Alembic
+-------
+
+Kallithea incorporates an [Alembic](http://alembic.zzzcomputing.com/en/latest/)
+"migration environment" in `kallithea/alembic`, portions of which is:
+
+Copyright © 2009-2016 by Michael Bayer.
+Alembic is a trademark of Michael Bayer.
+
+and licensed under the MIT-permissive license, which is
+[included in this distribution](MIT-Permissive-License.txt).
+
 
 Bootstrap
 ---------

MANIFEST.in

@@ -8,6 +8,7 b' include README.rst'
 include           development.ini
 recursive-include docs *
 recursive-include init.d *
+recursive-include kallithea/alembic *
 include           kallithea/bin/ldap_sync.conf
 include           kallithea/bin/template.ini.mako
 include           kallithea/config/deployment.ini_tmpl

setup.py

@@ -35,6 +35,7 b" callback = lambda V: ('.'.join(map(str, "
 is_windows = __platform__ in ['Windows']
 
 requirements = [
+    "alembic>=0.8.0,<0.9",
     "waitress==0.8.8",
     "webob>=1.0.8,<=1.1.1",
     "webtest==1.4.3",