old_contents: module.exports = function(grunt) {
  
  var srcFiles = [
      "src/core.js",
      "src/widgets.js",
      "src/widgets/input-integer.js",
      "src/renderer.js",
      "src/editor.js"
  ];
  
  grunt.initConfig({
      pkg: grunt.file.readJSON("package.json"),
      concat: {
          options: {
              banner: "/*! Perseus | http://github.com/Khan/perseus */\n",
              separator: ";"
          },
          dist: {
              src: srcFiles,
              dest: "build/perseus.js"
          }
      },
      uglify: {
          options: {
              banner: "/*! Perseus | http://github.com/Khan/perseus */\n"
          },
          build: {
              src: srcFiles,
              dest: "build/perseus.min.js"
          }
      }
  });
  
  grunt.loadNpmTasks("grunt-contrib-concat");
  grunt.loadNpmTasks("grunt-contrib-uglify");
  
  grunt.registerTask("default", ["concat", "uglify"]);
  
  };
  
new_contents: module.exports = function(grunt) {
  
  var srcFiles = [
      "src/core.js",
      "src/widgets.js",
      "src/widgets/input-integer.js",
      "src/renderer.js",
      "src/editor.js",
      "src/item-renderer.js"
  ];
  
  grunt.initConfig({
      pkg: grunt.file.readJSON("package.json"),
      concat: {
          options: {
              banner: "/*! Perseus | http://github.com/Khan/perseus */\n",
              separator: ";"
          },
          dist: {
              src: srcFiles,
              dest: "build/perseus.js"
          }
      },
      uglify: {
          options: {
              banner: "/*! Perseus | http://github.com/Khan/perseus */\n"
          },
          build: {
              src: srcFiles,
              dest: "build/perseus.min.js"
          }
      }
  });
  
  grunt.loadNpmTasks("grunt-contrib-concat");
  grunt.loadNpmTasks("grunt-contrib-uglify");
  
  grunt.registerTask("default", ["concat", "uglify"]);
  
  };
  
subject: Add item-renderer.js to build