fix: docker alembic

backend/alembic/env.py

@@ -1,4 +1,5 @@
 from logging.config import fileConfig
+import os
 
 from sqlalchemy import engine_from_config
 from sqlalchemy import pool
@@ -39,7 +40,10 @@ def run_migrations_offline() -> None:
     script output.
 
     """
-    url = config.get_main_option("sqlalchemy.url")
+    url = os.environ.get("DATABASE_URL") or os.environ.get("LETTERFEED_DATABASE_URL")
+    if url is None:
+        url = config.get_main_option("sqlalchemy.url")
+
     context.configure(
         url=url,
         target_metadata=target_metadata,
@@ -58,11 +62,21 @@ def run_migrations_online() -> None:
     and associate a connection with the context.
 
     """
-    connectable = engine_from_config(
-        config.get_section(config.config_ini_section, {}),
-        prefix="sqlalchemy.",
-        poolclass=pool.NullPool,
-    )
+    connectable = None
+    database_url = os.environ.get("DATABASE_URL") or os.environ.get("LETTERFEED_DATABASE_URL")
+
+    if database_url:
+        connectable = engine_from_config(
+            {"sqlalchemy.url": database_url},
+            prefix="sqlalchemy.",
+            poolclass=pool.NullPool,
+        )
+    else:
+        connectable = engine_from_config(
+            config.get_section(config.config_ini_section, {}),
+            prefix="sqlalchemy.",
+            poolclass=pool.NullPool,
+        )
 
     with connectable.connect() as connection:
         context.configure(