Set the default mysql database to subscan (#132)

* set database to subscan to match what the api is looking for

* reset readme

* comment some confusing vars

docker-compose.db.yml

@@ -5,7 +5,9 @@ services:
     image: mysql:5.7
     restart: always
     environment:
-      MYSQL_ROOT_PASSWORD: 'helloload'
+      # Name of the db created on start up
+      MYSQL_DATABASE: subscan
+      MYSQL_ROOT_PASSWORD: helloload
       MYSQL_ALLOW_EMPTY_PASSWORD: 'yes'
     ports:
       - '3306:3306'

docker-compose.yml

@@ -7,9 +7,13 @@ services:
     environment: &app_base
       MYSQL_HOST: mysql
       MYSQL_PASS: 'helloload'
+      # Name of the database subscan will connect to and use
+      # this db must exist
       MYSQL_DB: 'subscan'
       REDIS_ADDR: redis:6379
       CHAIN_WS_ENDPOINT: 'wss://rpc.polkadot.io'
+      # the types file used for the chain as:
+      # configs/source/{NETWORK_NODE}.json
       NETWORK_NODE: 'polkadot'
       WEB_HOST: 'http://subscan-api:4399'
       DEPLOY_ENV: 'prod'