Docker updates and maintenance (#164)

- Update run_daily.sh to use compose.yaml env var overrides if present on scheduled jobs, not just first run. Defaults back to config.json values if no override specified.
- update sample compose.yaml with volume mapping to keep config.json, accounts.json, and sessions folder persistent on local machine (e.g., to keep data persistent through updates).

compose.yaml

@@ -10,4 +10,13 @@ services:
       - CRON_START_TIME=0 5,11 * * *
       ### Run on start, set to false to only run the script per the cron schedule
       - RUN_ON_START=true 
-    restart: unless-stopped
+    volumes:
+      ### Replace "/path/to/" with the actual path to where you want to save the files on your local machine.
+      - /path/to/accounts.json:/usr/src/microsoft-rewards-script/dist/accounts.json
+      - /path/to/config.json:/usr/src/microsoft-rewards-script/dist/config.json 
+      - /path/to/sessions:/usr/src/microsoft-rewards-script/dist/browser/sessions #optional, saves your login session
+    deploy:
+      resources:
+        limits:
+          memory: 2048M    
+    restart: unless-stopped