CI: Set dist: trusty for Rubinius

.travis.yml

@@ -13,7 +13,6 @@ rvm:
   - 2.5.5
   - 2.6.2
   - ruby-head
-  - rbx-3.107
 
 gemfile:
   - gemfiles/rails_5_0.gemfile
@@ -23,6 +22,27 @@ gemfile:
   - gemfiles/rails_head.gemfile
 
 matrix:
+  include:
+    - name: "Rubinius - 5.0"
+      rvm: rbx-3.107
+      dist: trusty
+      gemfile: gemfiles/rails_5_0.gemfile
+    - name: "Rubinius - 5.1"
+      rvm: rbx-3.107
+      dist: trusty
+      gemfile: gemfiles/rails_5_1.gemfile
+    - name: "Rubinius - 5.2"
+      rvm: rbx-3.107
+      dist: trusty
+      gemfile: gemfiles/rails_5_2.gemfile
+    - name: "Rubinius - 6.0"
+      rvm: rbx-3.107
+      dist: trusty
+      gemfile: gemfiles/rails_6_0.gemfile
+    - name: "Rubinius - head"
+      rvm: rbx-3.107
+      dist: trusty
+      gemfile: gemfiles/rails_head.gemfile
   exclude:
     - rvm: 2.2.10
       gemfile: gemfiles/rails_6_0.gemfile

jbuilder.gemspec

@@ -11,6 +11,12 @@ Gem::Specification.new do |s|
 
   s.add_dependency 'activesupport', '>= 5.0.0'
 
+  if RUBY_ENGINE == 'rbx'
+    s.add_development_dependency('racc')
+    s.add_development_dependency('json')
+    s.add_development_dependency('rubysl')
+  end
+
   s.files         = `git ls-files`.split("\n")
   s.test_files    = `git ls-files -- test/*`.split("\n")
 end