Deprecate configuration helper

Using `Alchemy.config.get(:config_name)` is easier
to find than `configuration`.

Author: tvdeyen

lib/alchemy/configuration_methods.rb

@@ -12,9 +12,11 @@ module ConfigurationMethods
     #
     # Config file is in +config/alchemy/config.yml+
     #
+    # @deprecated - Use Alchemy.config.get instead
     def configuration(name)
       Alchemy.config.get(name)
     end
+    deprecate configuration: "Alchemy.config.get", deprecator: Alchemy::Deprecation
 
     # Returns true if more than one language is published on current site.
     #

spec/controllers/alchemy/base_controller_spec.rb

@@ -29,8 +29,10 @@ module Alchemy
 
     describe "#configuration" do
       it "returns certain configuration options" do
-        allow(Alchemy.config).to receive(:some_option).and_return(true)
-        expect(controller.configuration(:some_option)).to eq(true)
+        Deprecation.silenced do
+          allow(Alchemy.config).to receive(:some_option).and_return(true)
+          expect(controller.configuration(:some_option)).to eq(true)
+        end
       end
     end