Dockerfile fonts
diff --git a/docker/dev/Dockerfile b/docker/dev/Dockerfile
index f5c9b408b..964eda15f 100644
--- a/docker/dev/Dockerfile
+++ b/docker/dev/Dockerfile
@@ -8,6 +8,11 @@ RUN apk update && apk add --no-cache \
 # install go package.
 RUN go get github.com/mingrammer/round
 
+# install fonts
+RUN apk --no-cache add msttcorefonts-installer fontconfig && \
+    update-ms-fonts && \
+    fc-cache -f
+
 # add go bin to path.
 ENV PATH "$PATH:/root/go/bin"
 
@@ -18,4 +23,4 @@ WORKDIR /usr/src/diagrams
 COPY . .
 
 # install python requirements.
-RUN pip install black
+RUN pip install black graphviz jinja2

Docker file didn't work for me. Needed graphviz, jinja2 python packages, and fonts added.

Fixes #230 