more handling of env vars

alembic/env.py

@@ -5,15 +5,18 @@ from sqlalchemy import pool
 
 from alembic import context
 
+import os
+
 # 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.
 if config.config_file_name is not None:
     fileConfig(config.config_file_name)
 
+config.set_main_option("sqlalchemy.url", os.getenv("DB_URI"))
+
 # add your model's MetaData object here
 # for 'autogenerate' support
 # from myapp import mymodel