Chapter 4 – Building API Authentication

1. In order to create a user or sign them up, we need to define a HTTP handler with SignUpHandler as follows:

   func (handler *AuthHandler) SignUpHandler(c *gin.Context) {
      var user models.User
      if err := c.ShouldBindJSON(&user); err != nil {
          c.JSON(http.StatusBadRequest, gin.H{"error":                                            err.Error()})
          return
      }
      cur := handler.collection.FindOne(handler.ctx, bson.M{
          "username": user.Username,
      })
      if curTalent.Err() == mongo.ErrNoDocuments...