Adding models, DB access, signup, login

* Created Base, Auth, User and Admin models
* Added skeleton API structure containing: User signup, User & Admin
login, authorized zones, ping tests
* Simple user signup functional
* Skeleton user login functional, no means to verify as of yet
* Added POSTMAN file

models/user.go

@@ -0,0 +1,24 @@
+package models
+
+import (
+	"errors"
+
+	"github.com/yxzzy-wtf/gin-gonic-prepack/database"
+)
+
+type User struct {
+	Auth
+	Email string `gorm:"unique"`
+}
+
+func (u *User) GetJwt() (string, int) {
+	return "", 0
+}
+
+func (u *User) ByEmail(email string) error {
+	if err := database.Db.Where("email = ?", email).First(&u).Error; err != nil {
+		return errors.New("not found")
+	}
+
+	return nil
+}