add appraisal to run tests against multiple version of activerecord

Appraisals

@@ -0,0 +1,15 @@
+appraise "3.2" do
+  gem "activerecord", "~> 3.2.21"
+end
+
+appraise "4.0" do
+  gem "activerecord", "~> 4.0.0"
+end
+
+appraise "4.1" do
+  gem "activerecord", "~> 4.1.0"
+end
+
+appraise "4.2" do
+  gem "activerecord", "~> 4.2.0"
+end

gemfiles/3.2.gemfile

@@ -0,0 +1,7 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "activerecord", "~> 3.2.21"
+
+gemspec :path => "../"

gemfiles/4.0.gemfile

@@ -0,0 +1,7 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "activerecord", "~> 4.0.0"
+
+gemspec :path => "../"

gemfiles/4.1.gemfile

@@ -0,0 +1,7 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "activerecord", "~> 4.1.0"
+
+gemspec :path => "../"

gemfiles/4.2.gemfile

@@ -0,0 +1,7 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "activerecord", "~> 4.2.0"
+
+gemspec :path => "../"

sql_query.gemspec

@@ -30,4 +30,5 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "pry", "~> 0.10"
   spec.add_development_dependency "with_model", "~> 1.2"
   spec.add_development_dependency "codeclimate-test-reporter", "~> 0.4"
+  spec.add_development_dependency "appraisal"
 end