CI against rails 5.2

Author: amatsuda

.travis.yml

@@ -24,6 +24,7 @@ gemfile:
   - gemfiles/Gemfile-4-2-stable
   - gemfiles/Gemfile-5-0-stable
   - gemfiles/Gemfile-5-1-stable
+  - gemfiles/Gemfile-5-2-stable
   - gemfiles/Gemfile-edge
 
 matrix:
@@ -40,14 +41,20 @@ matrix:
       gemfile: gemfiles/Gemfile-5-0-stable
     - rvm: 1.9.3
       gemfile: gemfiles/Gemfile-5-1-stable
+    - rvm: 1.9.3
+      gemfile: gemfiles/Gemfile-5-2-stable
     - rvm: 2.0.0
       gemfile: gemfiles/Gemfile-5-0-stable
     - rvm: 2.0.0
       gemfile: gemfiles/Gemfile-5-1-stable
+    - rvm: 2.0.0
+      gemfile: gemfiles/Gemfile-5-2-stable
     - rvm: 2.1.10
       gemfile: gemfiles/Gemfile-5-0-stable
     - rvm: 2.1.10
       gemfile: gemfiles/Gemfile-5-1-stable
+    - rvm: 2.1.10
+      gemfile: gemfiles/Gemfile-5-2-stable
     - rvm: 1.9.3
       gemfile: gemfiles/Gemfile-edge
     - rvm: 2.0.0

gemfiles/Gemfile-5-2-stable

@@ -0,0 +1,5 @@
+source "https://rubygems.org"
+
+gemspec path: ".."
+
+gem "rails", github: "rails/rails", branch: "5-2-stable"