Allow `ask' action to customize choices prompt

spec/producer/core/prompter_spec.rb

@@ -19,7 +19,7 @@ module Producer::Core
 
     describe '#prompt' do
       let(:question)  { 'Which letter?' }
-      let(:choices)   { %w[A B] }
+      let(:choices)   { [[:a, ?A], [:b, ?B]] }
 
       it 'prompts choices' do
         prompter.prompt question, choices
@@ -34,7 +34,7 @@ module Producer::Core
       it 'returns value for entry chosen by user' do
         input.puts '1'
         input.rewind
-        expect(prompter.prompt question, choices).to eq 'B'
+        expect(prompter.prompt question, choices).to eq :b
       end
     end
   end

spec/producer/core/task/dsl_spec.rb

@@ -85,7 +85,7 @@ module Producer::Core
 
     describe '#ask' do
       let(:question)        { 'Which letter?' }
-      let(:choices)         { %w[A B] }
+      let(:choices)         { [[:a, ?A], [:b, ?B]] }
       let(:prompter_class)  { double('prompter class').as_null_object }
       subject(:ask)         { dsl.ask question, choices,
                               prompter: prompter_class }