[RxJS] Add debug method to Observable in TypeScript

Observable.prototype.debug = function(message: any) {
   return this.do(
     (next) => {
       if(!environment.production) {
         console.log(message, next);
       }
     },
     (err) => {
       if(!environment.production) {
         console.error(message, err)
       }
     },
     () => {
       if(!environment.production) {
         console.info("Observable completed", message)
       }
     }
   );
};

declare module 'rxjs/observable' {
  interface Observable<T> {
    debug: (...any) => Observable<T>
  }
}