Update to ruby 2.4.5

Author: podruh

Dockerfile

@@ -1,13 +1,11 @@
 # see https://docs.docker.com/engine/userguide/eng-image/dockerfile_best-practices/ for Dockerfile best practices
 
 # build me with:
-# docker build -t "juicymo/drone-ruby:2.5.1" .
+# docker build -t "juicymo/drone-ruby:2.4.5" .
 
-FROM alpine:3.8
+FROM ruby:2.4.5-alpine3.8
 MAINTAINER Tomas Jukin <tomas.jukin@juicymo.cz>
 
-RUN apk add --no-cache ruby=2.5.1-r2 ruby-bundler ruby-dev ruby-irb ruby-json ruby-rake ruby-rdoc
-
 ENV BUILD_PACKAGES curl-dev build-base bash cmake clang clang-dev make gcc g++ libc-dev linux-headers
 ENV RUBY_PACKAGES cairo-dev postgresql-dev tzdata wget postgresql=10.5-r0
 ENV WKHTMLTOPDF_PACKAGES gtk+ glib ttf-freefont fontconfig dbus

README.md

@@ -17,7 +17,7 @@ This is a Ruby image for [Drone](https://github.com/drone/drone), inspired by [4
 
 Intent of this image is CI testing of Ruby or Rails projects with Drone.
 
-This image supports `Drone 0.7.0` and `MRI Ruby 2.5.1`:
+This image supports `Drone 0.7.0` and `MRI Ruby 2.4.5`:
 
 It has a [bundler](http://bundler.io/) installed.
 
@@ -41,7 +41,7 @@ pipeline:
       - /tmp/cache:/cache
 
   build:
-    image: juicymo/drone-ruby
+    image: juicymo/drone-ruby:2.4.5
     environment:
       - RAILS_ENV=test
     commands:
@@ -57,7 +57,7 @@ pipeline:
     - /tmp/cache:/cache
 
   test:
-    image: juicymo/drone-ruby
+    image: juicymo/drone-ruby:2.4.5
     environment:
       - RAILS_ENV=test
       - DB_HOST=database