diff --git a/Dockerfile b/Dockerfile
index f2020aed70b8426d42eddb37f3b6d2fd74fce607..c5932bac5ff1af36467dc0f156d629e3e1ce0b93 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -19,7 +19,7 @@ ENV LC_CTYPE en_US.UTF-8
 # gettext: translations
 # java-cacerts: installs updated cacerts to /etc/ssl/certs/java/cacerts
 
-RUN apk add --update coreutils bash yarn git wget curl make gettext java-cacerts
+RUN apk add --no-cache coreutils bash yarn git wget curl make gettext java-cacerts
 
 # lein:    backend dependencies and building
 ADD https://raw.github.com/technomancy/leiningen/stable/bin/lein /usr/local/bin/lein
@@ -34,15 +34,15 @@ RUN /tmp/linux-install-1.10.1.708.sh
 # install dependencies before adding the rest of the source to maximize caching
 
 # backend dependencies
-ADD project.clj .
+COPY project.clj .
 RUN lein deps
 
 # frontend dependencies
-ADD yarn.lock package.json .yarnrc ./
+COPY yarn.lock package.json .yarnrc ./
 RUN yarn
 
 # add the rest of the source
-ADD . .
+COPY . .
 
 # build the app
 RUN INTERACTIVE=false bin/build
@@ -66,7 +66,7 @@ ENV FC_LANG en-US
 ENV LC_CTYPE en_US.UTF-8
 
 # dependencies
-RUN apk add --update bash ttf-dejavu fontconfig
+RUN apk add --no-cache bash ttf-dejavu fontconfig
 
 # add fixed cacerts
 COPY --from=builder /etc/ssl/certs/java/cacerts /opt/java/openjdk/lib/security/cacerts