use ENV variables instead of hardcoded values

frontend.dockerfile

@@ -1,8 +1,12 @@
 FROM php:7.0-apache
 
-ENV REACT_APP_TEST_URL=http://localhost:8000/api-wiaas \
-    REACT_APP_PROD_URL=http://localhost:8000/api-wiaas \
-    REACT_APP_DEV_URL=http://next.wiaas.saburly.com/api
+ARG REACT_APP_TEST_URL
+ARG REACT_APP_PROD_URL
+ARG REACT_APP_DEV_URL
+
+ENV REACT_APP_TEST_URL ${REACT_APP_TEST_URL}
+ENV REACT_APP_PROD_URL ${REACT_APP_PROD_URL}}
+ENV REACT_APP_DEV_URL ${REACT_APP_DEV_URL}
 
 RUN apt-get update && apt-get install -y git unzip gnupg
 RUN curl -sL https://deb.nodesource.com/setup_8.x | bash -