diff --git a/.gitignore b/.gitignore
index 082302f..5f6cfdc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,7 +2,7 @@
 *.env
 
 # Generated graph images:
-*.png
+charts/
 
 # Library roots:
 node_modules/
diff --git a/Dockerfile b/Dockerfile
index dc3951f..858e1e2 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,7 +3,7 @@ FROM nikolaik/python-nodejs:python3.9-nodejs16
 ENV PYTHONUNBUFFERED 1
 ENV PYTHONDONTWRITEBYTECODE 1
 
-WORKDIR ./waka-readme-stats
+WORKDIR /waka-readme-stats
 
 ADD requirements.txt ./requirements.txt
 RUN pip install --upgrade pip && pip install -r requirements.txt
diff --git a/Makefile b/Makefile
index 3cbd0ec..7c4a6ca 100644
--- a/Makefile
+++ b/Makefile
@@ -35,7 +35,7 @@ run-locally: venv node_modules
 run-container:
 	@ # Run action in container
 	docker build -t waka-readme-stats -f Dockerfile .
-	docker run --env-file .env.example waka-readme-stats
+	docker run --env-file .env.example -v ./charts:/waka-readme-stats/charts waka-readme-stats
 .PHONY: run-container
 
 
@@ -43,7 +43,8 @@ clean:
 	@ # Clean all build files, including: libraries, package manager configs, docker images and containers
 	rm -rf venv
 	rm -rf node_modules
-	rm -r package*.json
+	rm -f package*.json
+	rm -rf charts
 	docker rm -f waka-readme-stats 2>/dev/null || true
 	docker rmi $(docker images | grep "waka-readme-stats") 2> /dev/null || true
 .PHONY: clean
diff --git a/requirements.txt b/requirements.txt
index 18772a2..943bdc5 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,5 +4,6 @@ python-dotenv==0.17.0
 numpy==1.24.1
 pandas==1.2.3
 altair==4.1.0
+altair-saver==0.5.0
 pytz==2021.1
 humanize==3.3.0