added env var to dockerfile

Dockerfile

@@ -2,6 +2,9 @@ FROM node:20-bullseye-slim AS client-builder
 
 WORKDIR /client
 
+ARG REACT_APP_BACKEND_URL=http://localhost:3000
+ENV REACT_APP_BACKEND_URL=${REACT_APP_BACKEND_URL}
+
 # Copies flutter project
 COPY ./client /client
 
@@ -28,6 +31,8 @@ RUN chmod g+w /server/main.db;
 
 RUN ls -lh
 
+
+
 # Install node_modules and run project
 RUN npm install
 CMD npm run server