Task not found when grunt is run using load-grunt-config

Question

I am learning Grunt and want to use load-grunt-config to start with. Here is my code :

 Gruntfile.js  
  module.exports = function (grunt){
    var path = require('path');
    require('load-grunt-config')(grunt, {
      configPath: path.join(process.cwd(), 'grunt-tasks'),

    });
    grunt.registerTask('install',['test']);
  };

I have grunt-tasks folder in root directory of my project along with Gruntfile.js and in that I have included test.js

 test.js
 module.exports = {
    test :{
        local : {
        }
    }
 };

Now when I say grunt install from command line and using CWD as my project's root directory I get following error :

 Warning: Task "test" not found. Use --force to continue.

and when I include following segment in Gruntfile.js

  loadGruntTasks : {
        pattern : '*'
    }

I get following error :

>> Local Npm module "load-grunt-config" not found. Is it installed?
   Warning: Task "test" not found. Use --force to continue.

  May I know what I don't understand here?