diff --git a/10/Dockerfile b/10/Dockerfile
index 5158723..8757104 100644
--- a/10/Dockerfile
+++ b/10/Dockerfile
@@ -7,3 +7,5 @@ ENV REFRESHED_AT $REFRESHED_AT
 RUN apk add --no-cache \
   git \
   openssh
+
+RUN npm install -g yarn
diff --git a/12/Dockerfile b/12/Dockerfile
index 195afbb..5a5af03 100644
--- a/12/Dockerfile
+++ b/12/Dockerfile
@@ -7,3 +7,5 @@ ENV REFRESHED_AT $REFRESHED_AT
 RUN apk add --no-cache \
   git \
   openssh
+
+RUN npm install -g yarn