Update travis matrix

Author: estolfo

.travis.yml

@@ -4,11 +4,6 @@ sudo: false
 
 bundler_args: --without development
 
-rvm:
-  - 2.5
-  - ruby-head
-  - jruby-9.1.15.0
-
 branches:
   only:
   - master
@@ -20,20 +15,25 @@ before_install:
 
 matrix:
   fast_finish: true
-  allow_failures:
-    - rvm: ruby-head
-    - gemfile: gemfiles/rails_master.gemfile
   exclude:
     - rvm: ruby-head
       gemfile: gemfiles/rails_master.gemfile
     - rvm: jruby-9.1.15.0
       gemfile: gemfiles/rails_master.gemfile
     - rvm: jruby-9.1.15.0
       gemfile: gemfiles/driver_master.gemfile
-    - rvm: jruby-head
-      gemfile: gemfiles/driver_master.gemfile
-    - rvm: jruby-head
-      gemfile: gemfiles/rails_master.gemfile
+    - rvm: jruby-9.1.15.0
+      env: MONGODB=2.6.12
+    - rvm: jruby-9.1.15.0
+      env: MONGODB=3.4.10
+  allow_failures:
+    - rvm: ruby-head
+    - gemfile: gemfiles/rails_master.gemfile
+
+rvm:
+  - 2.5
+  - ruby-head
+  - jruby-9.1.15.0
 
 gemfile:
   - Gemfile