Update indexer to write sqlite db to persisted volume

indexer/Dockerfile

@@ -1,6 +1,9 @@
 FROM python:3.6-onbuild
 
-# ENV FLASK_APP=indexer/app.py
+RUN mkdir -p /config
+VOLUME /config
+
+ENV SQLALCHEMY_DATABASE_URI sqlite:////config/tokens.db
 ENV FLASK_DEBUG=1
 
 EXPOSE 5000

indexer/docker-compose.yml

@@ -2,6 +2,8 @@ version: '2'
 services:
   main:
     build: .
+    environment:
+      SQLALCHEMY_DATABASE_URI: sqlite:///tokens.db
     volumes:
       - .:/usr/src/app
     ports:

indexer/indexer/main.py

@@ -9,8 +9,10 @@ import flask
 
 
 app = flask.Flask(__name__)
-# TODO: use a real database or something
-app.config['SQLALCHEMY_DATABASE_URI'] = os.environ.get('DATABASE_URI', 'sqlite:///tokens.db')
+app.config['SQLALCHEMY_DATABASE_URI'] = os.environ.get(
+    'DATABASE_URI',
+    'sqlite:///tokens.db'
+)
 app.config['SQLALCHEMY_ECHO'] = True
 app.config['DEBUG'] = True