CODE EXAMPLE FOR JAVASCRIPT

Create an index in Mongodb

> db.col1.save({'colors': ['red','blue']})
> db.col1.ensureIndex({'colors':1})

> db.col1.find({'colors': 'red'})
{ "_id" : ObjectId("4ccc78f97cf9bdc2a2e54ee9"), "colors" : [ "red", "blue" ] }
> db.col1.find({'colors': 'blue'})
{ "_id" : ObjectId("4ccc78f97cf9bdc2a2e54ee9"), "colors" : [ "red", "blue" ] }