fix: Dockerfile to include .env

.dockerignore

@@ -10,4 +10,4 @@
 !/LICENSE
 !/README.md
 !/go.*
-!/.env
+!/.env.example

Dockerfile

@@ -33,7 +33,8 @@ COPY --from=build /build/ussd-africastalking .
 COPY --from=build /build/LICENSE .
 COPY --from=build /build/README.md .
 COPY --from=build /build/services ./services
-COPY --from=build /build/.env .
+COPY --from=build /build/.env.example .
+RUN mv .env.example .env
 
 EXPOSE 7123