Fix incorrect depenedency declaration

Author: owen-c

.travis.yml

@@ -19,9 +19,8 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
-  spec.add_dependency "activerecord", ">= 5.1"
-  spec.add_dependency "pg", "~> 1.1.3"
-
+  spec.add_development_dependency "activerecord", ">= 5.1"
+  spec.add_development_dependency "pg"
   spec.add_development_dependency "bundler", "~> 2.0"
   spec.add_development_dependency "rake", "~> 10.0"
   spec.add_development_dependency "rspec", "~> 3.0"