.travis.yml in razorpay-2.1.0 vs .travis.yml in razorpay-2.2.0

@@ -1,10 +1,26 @@
 language: ruby
-rvm:
-  - "2.1.10"
-  - "2.2.6"
-  - "2.3.3"
-  - "2.4.0"
+# List is from https://www.ruby-lang.org/en/downloads/branches/
+# Merged with whatever is the top of each branch at https://www.ruby-lang.org/en/downloads/releases/
+matrix:
+  include:
+    - rvm: "1.9.3"
+    - rvm: "2.0.0"
+    - rvm: "2.1.10"
+    - rvm: "2.2.9"
+    - rvm: "2.3.6"
+    - rvm: "2.4.2"
+    - rvm: "2.5.0"
+    - rvm: "2.5.0"
+      env: LINT=rubocop
+  allow_failures:
+  # These are EOL versions of ruby
+    - rvm: "1.9.3"
+    - rvm: "2.0.0"
+    - rvm: "2.1.10"
 before_install: gem update --system
 script:
   - bundle exec rake test
-  - bundle exec rake rubocop
+  - |
+    if [[ "$LINT" == "rubocop" ]] ; then
+      bundle exec rake rubocop
+    fi