[ACTIVEMODEL] Added injection of the paginate method when missing (…

…Kaminari)

The `paginate` method, needed for the import task, is injected in the class being imported
when the class implements Kaminari pagination, so the import Rake task works out of the box.

Closes karmi#191. Also see: karmi#48, karmi#108.

lib/tire/tasks.rb

@@ -67,6 +67,19 @@ def elapsed_to_human(elapsed)
 
     STDOUT.puts '-'*tty_cols
     elapsed = Benchmark.realtime do
+
+      # Add Kaminari-powered "paginate" method
+      #
+      if defined?(Kaminari) && klass.respond_to?(:page)
+        klass.instance_eval do
+          def paginate(options = {})
+            page(options[:page]).per(options[:per_page]).to_a
+          end
+        end
+      end unless klass.respond_to?(:paginate)
+
+      # Import the documents
+      #
       index.import(klass, 'paginate', params) do |documents|
 
         if total