feat: add Go models for User and UserProfile

- Create models/user.go with bcrypt password hashing
- Create models/user_profile.go with foreign key relationship
- Add GORM hooks for automatic profile creation
- Include proper JSON tags and database constraints

models/user_profile.go

@@ -0,0 +1,12 @@
+package models
+
+type UserProfile struct {
+	ID             uint   `gorm:"primaryKey" json:"id"`
+	UserID         uint   `gorm:"not null" json:"user_id"`
+	FirstName      string `gorm:"size:80;not null" json:"first_name"`
+	LastName       string `gorm:"size:80;not null" json:"last_name"`
+	Bio            string `gorm:"type:text" json:"bio"`
+	ProfilePicture string `gorm:"size:255" json:"profile_picture"`
+
+	User *User `gorm:"foreignKey:UserID" json:"user,omitempty"`
+}