title: How do I perform a find query in Mongoose?
body: <p>i have a collection of Ebooks data in mongodb like</p>
  
  <pre><code>{ 
      "_id" : ObjectId("58b56fe19585b10cd42981d8"), 
      "cover_path" : "D:\\Ebooks\\uploads\\ebooks\\cover\\1488285665748-img1-700x400.jpg", 
      "path" : "D:\\Ebooks\\uploads\\ebooks\\pdf\\1488285665257-Webservices Natraz.pdf", 
      "description" : "ebook", 
      "title" : "book name", 
      "tag" : [
          "Hindi", 
          "Other"
      ], 
      "__v" : NumberInt(0)
  }
  </code></pre>
  
  <p>Now i want to search something if keyword is little bit match from <code>"title:"</code> then show all related books object.</p>
  
  <p>My Mongoose schema is :-</p>
  
  <pre><code>var mongoose     = require('mongoose');
  var Schema       = mongoose.Schema;
  
  var EbookSchema   = new Schema({
      title: {type:String},
      description: {type:String},
      path: {type:String,required:true},
      cover_path: {type:String,required:true},
      tag: [{ type: String }]
  
  });
  module.exports = mongoose.model('Ebook', EbookSchema);
  </code></pre>
  
  <p>I try :-</p>
  
  <pre><code>app.get('/ebook?search=',function(req,res){
  var search_key = req.param('search');
      Ebook.find(title:'search',function(err, ebooks) {
              if (err)
                  res.send(err);
  
              res.json(ebooks);
          });
      });
  </code></pre>
  
  <p>but i found null how can i do ? i only want when i search a little-bit keyword i found all related object . </p>