diff --git a/Dockerfile b/Dockerfile
index bb6395d..e4ce4eb 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -4,7 +4,8 @@ FROM nginx:stable
 ARG GRAV_VERSION=1.5.8
 
 # Install dependencies
-RUN apt-get install software-properties-common && \
+RUN apt-get update && \
+    apt-get install software-properties-common && \
     add-apt-repository ppa:ondrej/php && \
     apt-get update && \
     apt-get install -y sudo wget unzip && \