Use latest Ruby patch releases in Travis build

.travis.yml

@@ -9,19 +9,10 @@ script:
   - ruby script/jack_hammer -t 2000
 matrix:
   include:
-    - rvm: 2.2.5
-      gemfile: spec/support/gemfiles/Gemfile.rails-3.2.x
-      env: DB=mysql
-    - rvm: 2.1.10
-      gemfile: spec/support/gemfiles/Gemfile.rails-4.2.x
-      env: DB=mysql
-    - rvm: 2.2.5
+    - rvm: 2.2.7
       gemfile: spec/support/gemfiles/Gemfile.rails-5.1.x
       env: DB=mysql
-    - rvm: 2.3.1
-      gemfile: spec/support/gemfiles/Gemfile.rails-4.1.x
-      env: DB=mysql
-    - rvm: 2.3.1
+    - rvm: 2.3.4
       gemfile: spec/support/gemfiles/Gemfile.rails-5.1.x
       env: DB=mysql
     - rvm: 2.4.1

README.md

@@ -22,14 +22,11 @@ DoubleEntry uses the [Money gem](https://github.com/RubyMoney/money) to encapsul
 DoubleEntry is tested against:
 
 Ruby
- * 2.1.x
  * 2.2.x
  * 2.3.x
  * 2.4.x
 
 Rails
- * 3.2.x
- * 4.1.x
  * 4.2.x
  * 5.0.x
  * 5.1.x