Warn when using pry-rails < 0.1.6. Close 983

lib/active_admin/dependency_checker.rb

@@ -9,6 +9,10 @@ def check!
             warn "ActiveAdmin requires meta_search >= 1.1.0.pre and sass-rails ~> 3.1.0.rc to work with rails >= 3.1.0"
           end
         end
+
+        unless pry_rails_0_1_6?
+          warn "ActiveAdmin is not compatible with pry-rails < 0.1.6. Please upgrade pry-rails."
+        end
       end
 
       def rails_3_1?
@@ -25,6 +29,14 @@ def sass_rails_3_1?
       rescue LoadError
         false
       end
+
+      def pry_rails_0_1_6?
+        begin
+          PryRails::VERSION < "0.1.6"
+        rescue NameError
+          false
+        end
+      end
     end
   end
 end