CI against rails 5.2

Author: amatsuda

.travis.yml

@@ -15,6 +15,7 @@ gemfile:
   - gemfiles/rails_4_2.gemfile
   - gemfiles/rails_5_0.gemfile
   - gemfiles/rails_5_1.gemfile
+  - gemfiles/rails_5_2.gemfile
   - gemfiles/rails_master.gemfile
   - Gemfile
 matrix:
@@ -27,6 +28,8 @@ matrix:
       gemfile: gemfiles/rails_5_0.gemfile
     - rvm: 2.6.3
       gemfile: gemfiles/rails_5_1.gemfile
+    - rvm: 2.6.3
+      gemfile: gemfiles/rails_5_2.gemfile
     - rvm: 2.5.5
       gemfile: gemfiles/rails_4_2.gemfile
     - rvm: 2.5.5

gemfiles/rails_5_2.gemfile

@@ -0,0 +1,10 @@
+source "https://rubygems.org"
+
+# Specify your gem's dependencies in active_record-observers.gemspec
+gem "rails", github: "rails/rails", branch: "5-2-stable"
+gem "minitest", "~> 5.8.4"
+gem "activeresource", github: "rails/activeresource"
+
+gem "mocha", require: false
+
+gemspec path: "../"