Test against Rails 5

Drop unmaintained versions of Ruby and Rails from the CI build matrix.
If you use those versions of Ruby and Rails, you can continue to use
previously released version of merit.

Upgrade Ambry dependency that works with Rails 5, with no XML
Serializer.

.travis.yml

@@ -3,16 +3,7 @@ sudo: false
 cache: bundler
 
 rvm:
-  - 2.0
-  - 2.1
-  - 2.2
+  - 2.3.0
 
 env:
-  - RAILS_VERSION=3.2
-  - RAILS_VERSION=4.1
-  - RAILS_VERSION=4.2
-
-matrix:
-  exclude:
-    - env: RAILS_VERSION=3.2
-      rvm: 2.2
+  - RAILS_VERSION=5.0

merit.gemspec

@@ -12,7 +12,7 @@ Gem::Specification.new do |s|
 
   s.required_ruby_version = '>= 1.9.2'
 
-  s.add_dependency 'ambry',  '~> 0.3.0'
+  s.add_dependency 'ambry',  '~> 1.0.0'
   s.add_development_dependency 'rails', '>= 3.2.0'
   s.add_development_dependency 'capybara'
   s.add_development_dependency 'simplecov'