Gorm Panic golang : panic serving runtime error: invalid memory address or nil pointer dereference

I'm trying to solve this panic error, i'm just created a backend in GOLANG, that code was my first steps, also if u see some mistakes, tell me!.

Here was the firts part of code , the Main: (main.go) into the package main:

if you see we have 2 functions

• main()

• BindRoutes(function()) -> it recieves a binder when it's called from the main

  func main() {
      err := godotenv.Load(".env")
      if err != nil {
          log.Fatal(err)
      }
  
      // Variables de la base de datos para el struct
      host := os.Getenv("POSTGRES_HOST")
      user := os.Getenv("POSTGRES_USER")
      port := os.Getenv("POSTGRES_PORT")
      password := os.Getenv("POSTGRES_PASSWORD")
      dbname := os.Getenv("POSTGRES_DB")
  
      // Variables del servidor
      PORT := os.Getenv("PORT")
      JWT_SECRET := os.Getenv("JWT_SECRET")
      DB_URL := os.Getenv("DATA_BASE_URL")
  
      server, err := server.NewServer(context.Background(), &server.Config{
          JWTSecret:   JWT_SECRET,
          Port:        PORT,
          DatabaseUrl: DB_URL,
      })
  
      if err != nil {
          log.Fatal(err)
      }
  
      db := config.Database{
          Host:     host,
          Port:     port,
          User:     user,
          Password: password,
          Dbname:   dbname,
      }
  
      db.Open()
  
      server.Start(BindRoutes)
  }
  
  func BindRoutes(s server.Server, r *mux.Router, db *config.Database) {
      r.HandleFunc("/blog/newblog", handler.CreateNewBlog(s, db)).Methods(http.MethodPost)
  }
  
  
  

Next we have the SERVER package

Here we have 2 structs and 1 interface, there the most important part is the binder, there I don't know if i implemented good.

```
package server

import (
    "context"
    "errors"
    "log"
    "net/http"

    "github.com/felipeolayao1998/backdiariodeuninge/config"
    "github.com/gorilla/mux"
)

type Config struct {
    Port        string
    JWTSecret   string
    DatabaseUrl string
}

type Server interface {
    Config() *Config
}

type Broker struct {
    config *Config
    router *mux.Router
}

func (b *Broker) Config() *Config {
    return b.config
}

func NewServer(ctx context.Context, config *Config) (*Broker, error) {
    if config.Port == "" {
        return nil, errors.New("port is required")
    }
    if config.JWTSecret == "" {
        return nil, errors.New("jwt secret is required")
    }
    if config.DatabaseUrl == "" {
        return nil, errors.New("database url is required")
    }
    broker := &Broker{
        config: config,
        router: mux.NewRouter(),
    }
    return broker, nil
}

func (b *Broker) Start(binder func(s Server, r *mux.Router, db *config.Database)) {
    b.router = mux.NewRouter()
    binder(b, b.router, &config.Database{})
    log.Println("starting server on port", b.config.Port)
    if err := http.ListenAndServe(b.config.Port, b.router); err != nil {
        log.Println("error starting server:", err)
    } else {
        log.Fatalf("server stopped")
    }
}

```

Models:

```
package Models

type Blog struct {
    Id      string `json:"id" gorm:"type:string;default:string;primary_key;unique"`
    Name    string `json:"name" gorm:"type:varchar(255);not null"`
    Content string `json:"content" gorm:"type:varchar(2000);not null"`
    Likes   int    `json:"likes" gorm:"type:integer" `
}

```

Handler: Here i have the problem, when i call the create, it returns an PANIC as you can see at the end of this question.

   func CreateNewBlog(s server.Server, db *config.Database) http.HandlerFunc {
       return func(w http.ResponseWriter, r *http.Request) {
           w.Header().Set("Content-type", "application/json")
           w.WriteHeader(http.StatusOK)
       
           db.Db.Create(&models.Blog{Id: "1", Name: "Felipe", Content: "fdasfasfa", Likes: 1}) //Here is the problem
   
       }
   }
   
2023/04/07 21:25:46 starting server on port :8000
   0xc00043a028 &{a2081199-a75e-4b3e-9551-3442a0fe0d21 Felipe contenido ejempo 1}
   2023/04/07 21:25:55 http: panic serving [::1]:59553: runtime error: invalid memory address or nil pointer dereference
   goroutine 18 [running]:
   net/http.(*conn).serve.func1()
           C:/Program Files/Go/src/net/http/server.go:1850 +0xbf
   panic({0x1620000, 0x1c52680})
           C:/Program Files/Go/src/runtime/panic.go:890 +0x262
   gorm.io/gorm.(*DB).Create(0x17e44c0?, {0x15d11c0?, 0xc00041c180?})
           C:/Users/Bymet/go/pkg/mod/gorm.io/[email protected]/finisher_api.go:18 +0x22
   github.com/felipeolayao1998/backdiariodeuninge/handler.CreateNewBlog.func1({0x17ea340, 0xc000424000}, 0xc00042c100)
           D:/PodCast/PaginaWeb/backend/handler/handlerBlog.go:69 +0x3e5