nodemon app crashed

[TheerejS]

[nodemon] 2.0.4

app_1 | [nodemon] to restart at any time, enter rs

app_1 | [nodemon] watching path(s): .

app_1 | [nodemon] watching extensions: js,mjs,json

app_1 | [nodemon] starting node server.js

app_1 | internal/modules/cjs/loader.js:638

app_1 | throw err;

app_1 | ^

app_1 |

app_1 | Error: Cannot find module 'restify'

app_1 | at Function.Module._resolveFilename (internal/modules/cjs/loader.js:636:15)

app_1 | at Function.Module._load (internal/modules/cjs/loader.js:562:25)

app_1 | at Module.require (internal/modules/cjs/loader.js:692:17)

app_1 | at require (internal/modules/cjs/helpers.js:25:18)

app_1 | at Object. (/usr/src/app/server.js:2:17)

app_1 | at Module._compile (internal/modules/cjs/loader.js:778:30)

app_1 | at Object.Module._extensions..js (internal/modules/cjs/loader.js:789:10)

app_1 | at Module.load (internal/modules/cjs/loader.js:653:32)

app_1 | at tryModuleLoad (internal/modules/cjs/loader.js:593:12)

app_1 | at Function.Module._load (internal/modules/cjs/loader.js:585:3)

app_1 | [nodemon] app crashed - waiting for file changes before starting...

help me how to run this.. thanks in advance