Optimize Dockerfile

Just merging RUNs to decrease the number of layers

Dockerfile

@@ -7,9 +7,8 @@ ENV MIX_ENV=prod
 RUN apk add git gcc g++ musl-dev make &&\
 	echo "import Mix.Config" > config/prod.secret.exs &&\
 	mix local.hex --force &&\
-	mix local.rebar --force
-
-RUN mix deps.get --only prod &&\
+	mix local.rebar --force &&\
+	mix deps.get --only prod &&\
 	mkdir release &&\
 	mix release --path release
 
@@ -20,9 +19,8 @@ ARG DATA=/var/lib/pleroma
 
 RUN echo "http://nl.alpinelinux.org/alpine/latest-stable/community" >> /etc/apk/repositories &&\
 	apk update &&\
-	apk add ncurses postgresql-client
-
-RUN adduser --system --shell /bin/false --home ${HOME} pleroma &&\
+	apk add ncurses postgresql-client &&\
+	adduser --system --shell /bin/false --home ${HOME} pleroma &&\
 	mkdir -p ${DATA}/uploads &&\
 	mkdir -p ${DATA}/static &&\
 	chown -R pleroma ${DATA} &&\