chore: properly add default port and blog name value

data/entrypoint.sh

@@ -13,7 +13,7 @@ export SITE_PATH="/app/jekyll/$BLOG_NAME"
 export SITE_TITLE=$SITE_TITLE
 export THEME=$THEME
 export TWITTER_USERNAME=$TWITTER_USERNAME
-export WWW_PORT=${WWW_PORT:-4000}
+export WWW_PORT=$WWW_PORT
 export URL=$URL
 
 update_config() {

docker-compose.yml

@@ -5,11 +5,11 @@ services:
     build:
       context: ${PWD}
       args:
-        BLOG_NAME: ${BLOG_NAME}
+        BLOG_NAME: ${BLOG_NAME:-blog}
     env_file: ${PWD}/data/.env
     ports:
-      - ${LIVERELOAD_PORT}:10000
-      - ${WWW_PORT}:4000
+      - ${LIVERELOAD_PORT:-10000}:10000
+      - ${WWW_PORT:-4000}:4000
     volumes:
       - ${PWD}/jekyll:/app/jekyll
       - ${PWD}/data:/opt/jekyll