Change compose layout to use env file

.gitignore

@@ -1,4 +1,4 @@
-.env/*
+.env*
 *.pyc
 *_design1
 fet2020/.env/*

docker-compose.yml

@@ -18,15 +18,15 @@ services:
     container_name: django-container
     image: django-image:latest
     environment:
-      HOST_NAME: "fet.at"
-      DEBUG: "False"
-      LDAP: "True"
-      SECRET_KEY: "sae34sADfrFr89E!Gl#f!34hdjGR#!jopi4qFEr#4R56rT56zT2#wE1!feGp"
-      MYSQL_USER: "user"
-      MYSQL_PASSWORD: "hgu"
-      ETHERPAD_GROUP: "g.snlbqn7S6ksRbom3"
-      EMAIL_HOST_USER: "verleih@fet.at"
-      EMAIL_HOST_PASSWORD: ""
+      HOST_NAME: ${HOSTNAME}
+      DEBUG: ${DEBUG}
+      LDAP: ${LDAP}
+      SECRET_KEY: ${SECRET_KEY}
+      MYSQL_USER: ${DJANGO_MYSQL_USER}
+      MYSQL_PASSWORD: ${DJANGO_MYSQL_PASSWORD}
+      ETHERPAD_GROUP: ${ETHERPAD_GROUP}
+      EMAIL_HOST_USER: ${EMAIL_HOST_USER}
+      EMAIL_HOST_PASSWORD: ${EMAIL_HOST_PASSWORD}
     depends_on:
       mysql:
         condition: service_healthy
@@ -55,8 +55,8 @@ services:
       DB_HOST: etherpadsql
       DB_PORT: 3306
       DB_NAME: etherpaddb
-      DB_USER: user
-      DB_PASS: "hgu"
+      DB_USER: ${ETHERPAD_DB_USER}
+      DB_PASS: ${ETHERPAD_DB_PASSWORD}
       DB_CHARSET: "utf8mb4"
       TRUST_PROXY: false
       AUTHENTICATION_METHOD: "apikey"
@@ -79,8 +79,8 @@ services:
     image: mariadb:10.7
     environment:
       MYSQL_DATABASE: fet2020db
-      MYSQL_USER: user
-      MYSQL_PASSWORD: hgu
+      MYSQL_USER: ${DJANGO_MYSQL_USER}
+      MYSQL_PASSWORD: ${DJANGO_MYSQL_PASSWORD}
       MYSQL_COLLATION: utf8_general_ci
       MYSQL_CHARSET: utf8
       MYSQL_ALLOW_EMPTY_PASSWORD: "yes"
@@ -98,8 +98,8 @@ services:
     image: mariadb:10.7
     environment:
       MYSQL_DATABASE: etherpaddb
-      MYSQL_USER: user
-      MYSQL_PASSWORD: "hgu"
+      MYSQL_USER: ${ETHERPAD_DB_USER}
+      MYSQL_PASSWORD: ${ETHERPAD_DB_PASSWORD}
       MYSQL_COLLATION: utf8_general_ci
       MYSQL_CHARSET: utf8
       MYSQL_ALLOW_EMPTY_PASSWORD: "yes"