hapi-auth-bearer-token: Error: Unknown authentication strategy

I am trying to use this module to enable bearer token on my app. However, I am getting the error shown in the title.

I have been stuck for days now. Hoping anyone could help me.

I have user.js route

module.exports = [{
    'method' : 'GET',
    'path' : '/v1/users',
    'config' : {
        'handler' : function (request, reply) {
            User.find(function (error, data) {
                if (!error) {
                    reply(data)
                        .code(200)
                }
            });
        },
        'auth' : 'simple'
    }
}];

Now, inside my server.js,

Server.register([{
    'register' : require('hapi-auth-bearer-token')
}, {
    'register' : require('./api')
}], function (error) {
    if (!error) {
        Server.auth.strategy('simple', 'bearer-access-token', {
            'validateFunc' : function (token, callback) {
                if (token === "1234") {
                    callback(null, true, {
                        'token' : token
                    })
                } else {
                    callback(null, false, {
                        'token' : token
                    })
                }
            }
        });

        Server.start(function () {
            console.log('info', 'Server running at ' + Server.info.uri);
        });
    }
});

But I get Error: Unknown authentication strategy: simple in path: /v1/users

Complete error message:

    at Object.exports.assert (/var/nodevagrant/project/Interest/node_modules/hapi/node_modules/hoek/lib/index.js:663:11)
    at /var/nodevagrant/project/Interest/node_modules/hapi/lib/auth.js:139:14
    at Array.forEach (native)
    at internals.Auth._setupRoute (/var/nodevagrant/project/Interest/node_modules/hapi/lib/auth.js:136:24)
    at new module.exports.internals.Route (/var/nodevagrant/project/Interest/node_modules/hapi/lib/route.js:131:47)
    at internals.Connection._addRoute (/var/nodevagrant/project/Interest/node_modules/hapi/lib/connection.js:342:17)
    at internals.Connection._route (/var/nodevagrant/project/Interest/node_modules/hapi/lib/connection.js:334:18)
    at internals.Plugin._apply (/var/nodevagrant/project/Interest/node_modules/hapi/lib/plugin.js:432:14)
    at internals.Plugin.route (/var/nodevagrant/project/Interest/node_modules/hapi/lib/plugin.js:407:10)
    at Object.exports.register (/var/nodevagrant/project/Interest/api/index.js:8:9)