feedback.ts

  postFeedback(feedback){
    return new Promise(
      (resolve,reject)=>{
        let headers = new Headers(
          {
             'Content-Type': 'application/json'
          }
        )
        let options = new RequestOptions(
          {
            headers:headers
          }
        )

        this.http.post("http://localhost:7050/feedbacks",
        feedback,
        options
        )
        .subscribe(data =>{
          resolve(data)
        },
        errData =>{
            reject(errData)
        } 
        )
      }
    )

  }