.travis.yml in devise-4.3.0 vs .travis.yml in devise-4.4.0

@@ -1,12 +1,13 @@
 language: ruby
 
 rvm:
   - 2.1.10
-  - 2.2.7
-  - 2.3.4
-  - 2.4.1
+  - 2.2.8
+  - 2.3.5
+  - 2.4.2
+  - 2.5.0
   - ruby-head
 
 gemfile:
   - Gemfile
   - gemfiles/Gemfile.rails-5.0-stable
@@ -15,12 +16,14 @@
 
 matrix:
   exclude:
     - rvm: 2.1.10
       gemfile: Gemfile
-    - rvm: 2.4.1
+    - rvm: 2.5.0
       gemfile: gemfiles/Gemfile.rails-4.1-stable
+    - rvm: 2.4.2
+      gemfile: gemfiles/Gemfile.rails-4.1-stable
     - rvm: ruby-head
       gemfile: gemfiles/Gemfile.rails-4.1-stable
     - rvm: 2.1.10
       gemfile: gemfiles/Gemfile.rails-5.0-stable
     - rvm: 2.1.10
@@ -41,10 +44,12 @@
 env:
   matrix:
     - DEVISE_ORM=active_record
     - DEVISE_ORM=mongoid
 
-before_install: "rm ${BUNDLE_GEMFILE}.lock"
+before_install:
+  - "rm ${BUNDLE_GEMFILE}.lock"
+  - gem update --system
 
 before_script: "bundle update"
 
 script: "bin/test"