diff --git a/.travis.yml b/.travis.yml
index c81844d..9144cf7 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,9 +8,6 @@ cache:
     - api/node_modules
     - web/node_modules
 
-environment:
-  CHILD_CONCURRENCY: 1
-
 script:
   - ./script/unittestweb
   - ./script/unittestapi
diff --git a/web/Dockerfile b/web/Dockerfile
index 9dded92..e3a2541 100644
--- a/web/Dockerfile
+++ b/web/Dockerfile
@@ -1,5 +1,6 @@
 FROM node:latest AS build
 WORKDIR /app
+ENV CHILD_CONCURRENCY 1
 COPY package*.json ./
 RUN npm install
 COPY . .