add two new models - Answer and Question

internal/models/answer.go

@@ -0,0 +1,49 @@
+package models
+
+import (
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+)
+
+type Answer string
+
+const (
+	AnswerA Answer = "a"
+	AnswerB Answer = "b"
+	AnswerC Answer = "c"
+	AnswerD Answer = "d"
+)
+
+func (role Answer) IsValid() bool {
+	switch role {
+	case AnswerA,
+		AnswerB,
+		AnswerC,
+		AnswerD:
+		return true
+	}
+	return false
+}
+
+func (answer Answer) String() string {
+	return string(answer)
+}
+
+func (answer *Answer) UnmarshalGQL(v interface{}) error {
+	str, ok := v.(string)
+	if !ok {
+		return fmt.Errorf("enums must be strings")
+	}
+
+	*answer = Answer(strings.ToLower(str))
+	if !answer.IsValid() {
+		return fmt.Errorf("%s is not a valid Answer", str)
+	}
+	return nil
+}
+
+func (answer Answer) MarshalGQL(w io.Writer) {
+	fmt.Fprint(w, strconv.Quote(answer.String()))
+}

internal/models/question.go

@@ -0,0 +1,32 @@
+package models
+
+import (
+	"context"
+	"time"
+)
+
+type Question struct {
+	ID              int            `json:"id" xml:"id" gqlgen:"id"`
+	From            string         `pg:",unique:group_1" json:"from" xml:"from" gqlgen:"from"`
+	Content         string         `pg:",unique:group_1,notnull" json:"content" xml:"content" gqlgen:"content"`
+	Explanation     string         `json:"explanation" xml:"explanation" gqlgen:"explanation"`
+	CorrectAnswer   Answer         `pg:",unique:group_1,notnull" json:"correctAnswer" xml:"correctAnswer" gqlgen:"correctAnswer"`
+	Image           string         `json:"image" xml:"image" gqlgen:"image"`
+	AnswerA         Answer         `json:"answerA" xml:"answerA" gqlgen:"answerA"`
+	AnswerAImage    string         `json:"answerAImage" xml:"answerAImage" gqlgen:"answerAImage"`
+	AnswerB         Answer         `json:"answerB" xml:"answerB" gqlgen:"answerB"`
+	AnswerBImage    string         `json:"answerBImage" xml:"answerBImage" gqlgen:"answerBImage"`
+	AnswerC         Answer         `json:"answerC" xml:"answerC" gqlgen:"answerC"`
+	AnswerCImage    string         `json:"answerCImage" xml:"answerCImage" gqlgen:"answerCImage"`
+	AnswerD         Answer         `json:"answerD" xml:"answerD" gqlgen:"answerD"`
+	AnswerDImage    string         `json:"answerDImage" xml:"answerDImage" gqlgen:"answerDImage"`
+	QualificationID int            `pg:",unique:group_1,notnull" json:"qualificationID" xml:"qualificationID" gqlgen:"qualificationID"`
+	Qualification   *Qualification `pg:"rel:has-one" json:"qualification" xml:"qualification" gqlgen:"qualification"`
+	CreatedAt       time.Time      `json:"createdAt,omitempty" pg:"default:now()" xml:"createdAt" gqlgen:"createdAt"`
+}
+
+func (q *Question) BeforeInsert(ctx context.Context) (context.Context, error) {
+	q.CreatedAt = time.Now()
+
+	return ctx, nil
+}