fix 2.6 builds

Author: Sam Phippen

.travis.yml

@@ -38,15 +38,15 @@ matrix:
   include:
     # Rails dev / 6 builds >= 2.4.4
     - rvm: 2.6.0
-      env: RAILS_VERSION='~> 4.2.0'
+      env: RAILS_VERSION=master
     - rvm: 2.5.3
       env: RAILS_VERSION=master
     - rvm: 2.4.4
       env: RAILS_VERSION=master
 
     # Rails 5.2 builds >= 2.2.2
     - rvm: 2.6.0
-      env: RAILS_VERSION='~> 4.2.0'
+      env: RAILS_VERSION='~> 5.2.0'
     - rvm: 2.5.3
       env: RAILS_VERSION='~> 5.2.0'
     - rvm: 2.4.4
@@ -56,7 +56,7 @@ matrix:
 
     # Rails 5.1 Builds >= 2.2.2
     - rvm: 2.6.0
-      env: RAILS_VERSION='~> 4.2.0'
+      env: RAILS_VERSION='~> 5.1.0'
     - rvm: 2.5.3
       env: RAILS_VERSION='~> 5.1.0'
     - rvm: 2.4.4
@@ -66,7 +66,7 @@ matrix:
 
     # Rails 5.0 Builds >= 2.2.2
     - rvm: 2.6.0
-      env: RAILS_VERSION='~> 4.2.0'
+      env: RAILS_VERSION='~> 5.0.0'
     - rvm: 2.5.3
       env: RAILS_VERSION='~> 5.0.0'
     - rvm: 2.4.4