Update ruby to 2.5.0 (#166)

* Update ruby to 2.5.0

* Update image version

* Update CHANGELOG.md

CHANGELOG.md

@@ -1,5 +1,9 @@
 ## UPCOMING
 
+## `v2018_01_08_1`
+
+* `Ruby`: `2.5.0`
+
 ## `v2017_12_21_1`
 
 * `Ruby`: `2.4.3`

Dockerfile

@@ -22,7 +22,7 @@ ENV LANG="en_US.UTF-8" \
 
 # Configs - tool versions
     TOOL_VER_BITRISE_CLI="1.11.0" \
-    TOOL_VER_RUBY="2.4.3" \
+    TOOL_VER_RUBY="2.5.0" \
     TOOL_VER_GO="1.9.2" \
     TOOL_VER_DOCKER="17.06.2" \
     TOOL_VER_DOCKER_COMPOSE="1.16.0"
@@ -99,8 +99,7 @@ RUN DEBIAN_FRONTEND=noninteractive apt-get -y install \
 # cleanup
  && cd / \
  && rm -rf /tmp/ruby-inst \
-# gem install bundler & rubygem update
- && gem install bundler --no-document \
+# gem install rubygem update
  && gem update --system --no-document
 
 
@@ -195,5 +194,5 @@ RUN DEBIAN_FRONTEND=noninteractive apt-get -y install git-lfs \
 
 WORKDIR $BITRISE_SOURCE_DIR
 
-ENV BITRISE_DOCKER_REV_NUMBER_BASE v2017_12_21_1
+ENV BITRISE_DOCKER_REV_NUMBER_BASE v2018_01_08_1
 CMD bitrise --version