chore: docker-compose mysql 설정값 환경 변수로 추출

Author: nilgil

.gitignore

@@ -1,3 +1,4 @@
+.env
 data.sql
 application.properties
 HELP.md

compose.yaml

@@ -2,9 +2,9 @@ services:
   mysql:
     image: 'mysql:latest'
     environment:
-      - 'MYSQL_DATABASE=gcm'
-      - 'MYSQL_ROOT_PASSWORD=verysecret'
-      - 'MYSQL_USER=nilgil'
-      - 'MYSQL_PASSWORD=secret'
+      - MYSQL_DATABASE=${MYSQL_DATABASE}
+      - MYSQL_ROOT_PASSWORD=${MYSQL_ROOT_PASSWORD}
+      - MYSQL_USER=${MYSQL_USER}
+      - MYSQL_PASSWORD=${MYSQL_PASSWORD}
     ports:
       - '3306:3306'