Getting error while using modal-dialog in ember.js

I just add the basic modal-dialog code But I am getting the error.

app/templates/application.hbs

Hi Guys!!

I am getting this error.

Uncaught Error: Attempted to resolve `modal-dialog`, which was expected to be a component, but nothing was found.
    at resolveComponent (opcode-compiler.js:234)
    at encodeOp (opcode-compiler.js:2583)
    at pushOp (opcode-compiler.js:2507)
    at opcode-compiler.js:2287
    at Compilers.compile (opcode-compiler.js:519)
    at compileStatements (opcode-compiler.js:2511)
    at maybeCompile (opcode-compiler.js:2490)
    at CompilableTemplateImpl.compile (opcode-compiler.js:2470)
    at Object.evaluate (runtime.js:3614)
    at AppendOpcodes.evaluate (runtime.js:1284)