diff --git a/Dockerfile.ci b/Dockerfile.ci
index f836119cf..7f75f1a9e 100644
--- a/Dockerfile.ci
+++ b/Dockerfile.ci
@@ -9,6 +9,6 @@ WORKDIR $WORKDIR
 
 COPY . $WORKDIR
 
-RUN RAILS_MAIN=true bundle install --jobs `expr $(cat /proc/cpuinfo | grep -c "cpu cores") - 1` --retry 3
+RUN RAILS_MAIN=1 bundle install --jobs `expr $(cat /proc/cpuinfo | grep -c "cpu cores") - 1` --retry 3
 
 CMD ["sh"]
diff --git a/Gemfile b/Gemfile
index 2c20d1022..0d0761ba0 100644
--- a/Gemfile
+++ b/Gemfile
@@ -16,7 +16,7 @@ gem "msgpack", ">= 1.7.0"
 
 if ENV["RAILS_SOURCE"]
   gemspec path: ENV["RAILS_SOURCE"]
-elsif ENV["RAILS_MAIN"] == 'true'
+elsif ENV["RAILS_MAIN"]
   gem "rails", github: "rails/rails", branch: 'main'
 else
   # Need to get rails source because the gem doesn't include tests
diff --git a/docker-compose.ci.yml b/docker-compose.ci.yml
index c26dc6c9c..82c48d48a 100644
--- a/docker-compose.ci.yml
+++ b/docker-compose.ci.yml
@@ -5,7 +5,7 @@ services:
   ci:
     environment:
       - ACTIVERECORD_UNITTEST_HOST=sqlserver
-      - RAILS_MAIN=true
+      - RAILS_MAIN=1
     build:
       context: .
       dockerfile: Dockerfile.ci