.travis.yml in rack-nullsession-0.0.1 vs .travis.yml in rack-nullsession-1.0.0

@@ -1,11 +1,11 @@
+# In order to install old Rubies, we need to use old Ubuntu distibution.
+dist: trusty
 language: ruby
+before_install:
+  - "script/update_rubygems_and_install_bundler"
 rvm:
-  - 1.9.3
-  - 1.9.2
-  - jruby-18mode
-  - jruby-19mode
-  - rbx-18mode
-  - rbx-19mode
-  - ruby-head
-  - 1.8.7
-  - ree
+  - 2.7.1
+  - 2.6.6
+  - 2.5.8
+  - 2.4.10
+  - 2.3.8