Put upstream host URLs into env

docker-compose.yml

@@ -11,5 +11,7 @@ services:
 
   frontend:
     build: ./frontend
+    env_file:
+      - ./frontend/nginx/.env
     ports:
       - "80:80"

frontend/nginx/.env.sample

@@ -0,0 +1,3 @@
+QUACK=quack
+QUESTION_SERVICE_URL=http://question:3002/
+USER_SERVICE_URL=http://user:3001/

frontend/nginx/nginx.conf

@@ -8,5 +8,5 @@ events {
 
 http {
     include /etc/nginx/mime.types;
-    include /etc/nginx/sites-enabled/*;
+    include /etc/nginx/conf.d/app.conf;
 }

frontend/nginx/sites-enabled/app.conf → frontend/nginx/templates/app.conf.template

@@ -7,10 +7,10 @@ server {
     }
 
     location /api/questions/ {
-        proxy_pass http://question:3002/;
+        proxy_pass ${QUESTION_SERVICE_URL};
     }
 
     location /api/users/ {
-        proxy_pass http://user:3001/;
+        proxy_pass ${USER_SERVICE_URL};
     }
 }