Add alembic plumbing for database schema migrations.

data/migrations/env.py

@@ -0,0 +1,76 @@
+from __future__ import with_statement
+from alembic import context
+from sqlalchemy import engine_from_config, pool
+from logging.config import fileConfig
+
+from data.database import all_models
+from app import app
+from data.model.sqlalchemybridge import gen_sqlalchemy_metadata
+
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+config.set_main_option('sqlalchemy.url', app.config['DB_URI'])
+
+# 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 = gen_sqlalchemy_metadata(all_models)
+
+# 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 = app.config['DB_CONNECTION']
+    context.configure(url=url, target_metadata=target_metadata)
+
+    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.
+
+    """
+    engine = engine_from_config(
+                config.get_section(config.config_ini_section),
+                prefix='sqlalchemy.',
+                poolclass=pool.NullPool)
+
+    connection = engine.connect()
+    context.configure(
+                connection=connection,
+                target_metadata=target_metadata
+                )
+
+    try:
+        with context.begin_transaction():
+            context.run_migrations()
+    finally:
+        connection.close()
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()
+