Update Travis gemfiles.

Author: cblunt

.travis.yml

@@ -4,7 +4,7 @@ rvm:
   - 2.0.0
   - 2.2.2
 gemfile:
-  - gemfiles/4.0.gemfile
-  - gemfiles/4.1.gemfile
-  - gemfiles/4.2.gemfile
+  - gemfiles/5.0.gemfile
+  - gemfiles/5.1.gemfile
+  - gemfiles/5.2.gemfile
 script: "bundle exec rake clean test"

gemfiles/4.0.gemfile.lock

@@ -2,6 +2,6 @@
 
 source "https://rubygems.org"
 
-gem "rails", "~> 4.0.0"
+gem "rails", "~> 5.0.0"
 
 gemspec :path => "../"

gemfiles/4.1.gemfile.lock

@@ -2,6 +2,6 @@
 
 source "https://rubygems.org"
 
-gem "rails", "~> 4.2.3"
+gem "rails", "~> 5.1.0"
 
 gemspec :path => "../"

gemfiles/4.2.gemfile.lock

@@ -2,6 +2,6 @@
 
 source "https://rubygems.org"
 
-gem "rails", "~> 4.1.12"
+gem "rails", "~> 5.2.0"
 
 gemspec :path => "../"