diff --git a/Dockerfile b/Dockerfile
index 345ea0f7..3e860f96 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,15 +2,15 @@ FROM python:3
 
 WORKDIR /app
 
-ADD requirements.txt /app/requirements.txt
+COPY requirements.txt /app/requirements.txt
 
 RUN pip install -r requirements.txt
 
-ADD asana /app/asana
-ADD examples /app/examples
-ADD tests /app/tests
-ADD setup.py /app/setup.py
-ADD README.md /app/README.md
+COPY asana /app/asana
+COPY examples /app/examples
+COPY tests /app/tests
+COPY setup.py /app/setup.py
+COPY README.md /app/README.md
 
 RUN find . -name '*.pyc' -delete