diff --git a/Dockerfile b/Dockerfile
index 00f2006..3ce651c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -56,6 +56,7 @@ FROM runtime-base AS production
 ENV RAILS_ENV=production
 
 COPY --from=bundle-production /usr/local/bundle /usr/local/bundle
+COPY Gemfile Gemfile.lock /app/
 COPY app /app/app
 COPY bin /app/bin
 COPY config /app/config
@@ -83,6 +84,7 @@ RUN apt-get update -qq \
     && python3 -m pip install --no-cache-dir invoke
 
 COPY --from=bundle-test /usr/local/bundle /usr/local/bundle
+COPY Gemfile Gemfile.lock /app/
 COPY app /app/app
 COPY bin /app/bin
 COPY config /app/config
diff --git a/tasks.py b/tasks.py
index af6fa28..96f2020 100644
--- a/tasks.py
+++ b/tasks.py
@@ -49,9 +49,10 @@ BLACKBOX_MAILGUN_API_KEY = "blackbox-test-api-key"
 BLACKBOX_MAILGUN_DOMAIN = "blackbox.example.com"
 SPEC_ROOT = Path("spec")
 E2E_SPEC_ROOT = SPEC_ROOT / "e2e" / "http"
-BUNDLER_VERSION = Path("Gemfile.lock").read_text(encoding="utf-8").split("BUNDLED WITH", 1)[1].strip().splitlines()[-1].strip()
 ROOT = Path(__file__).resolve().parent
 DB_DIR = ROOT / "db"
+GEMFILE_LOCK_PATH = ROOT / "Gemfile.lock"
+BUNDLER_VERSION = GEMFILE_LOCK_PATH.read_text(encoding="utf-8").split("BUNDLED WITH", 1)[1].strip().splitlines()[-1].strip()
 
 
 def _env(**overrides):