Heroku Website : Application Error

Im a beginner and I am trying to upload my website to heroku, it said it was successful but when I click the link; it says there is an application error: My code is below. I have the log from heroku below, and I also have my package.json file attached at the bottom.

 -----> Node.js app detected
        -----> Creating runtime environment

               NPM_CONFIG_LOGLEVEL=error
               NPM_CONFIG_PRODUCTION=true
               NODE_VERBOSE=false
               NODE_ENV=production
               NODE_MODULES_CACHE=true
        -----> Installing binaries
               engines.node (package.json):  unspecified
               engines.npm (package.json):   unspecified (use default)

               Resolving node version 6.x via semver.io...
               Downloading and installing node 6.10.3...
               Using default npm version: 3.10.10
        -----> Restoring cache
               Loading 2 from cacheDirectories (default):
               - node_modules
               - bower_components (not cached - skipping)
        -----> Building dependencies
               Installing node modules (package.json)
        -----> Caching build
               Clearing previous node cache
               Saving 2 cacheDirectories (default):
               - node_modules
               - bower_components (nothing to cache)
        -----> Build succeeded!
        -----> Discovering process types
               Procfile declares types     -> (none)
               Default types for buildpack -> web
        -----> Compressing...
               Done: 14.8M
        -----> Launching...
               Released v5
        {
      "name": "freelancer",
      "title": "Freelancer",
      "version": "3.3.7+1",
      "homepage": "http://startbootstrap.com/template-overviews/freelancer",
      "author": "Start Bootstrap",
      "scripts": {
        "start": "node app.js"
      },
      "license": {
        "type": "MIT",
        "url": "https://github.com/BlackrockDigital/startbootstrap/blob/gh-pages/LICENSE"
      },
      "devDependencies": {
        "bootstrap": "^3.3.7",
        "browser-sync": "^2.13.0",
        "font-awesome": "^4.6.3",
        "gulp": "^3.9.1",
        "gulp-clean-css": "^2.0.10",
        "gulp-filter": "^4.0.0",
        "gulp-header": "^1.8.7",
        "gulp-less": "^3.1.0",
        "gulp-rename": "^1.2.2",
        "gulp-uglify": "^1.5.4",
        "jquery": "^1.11.3"
      },
      "repository": {
        "type": "git",
        "url": "https://github.com/BlackrockDigital/startbootstrap-freelancer.git"
      }
    }

via Kim Riegel