refactor:

internal/models/contest.go

@@ -0,0 +1,8 @@
+package models
+
+type Contest struct {
+	Id   *int    `db:"id"`
+	Name *string `db:"name"`
+	//CreatedAt   time.Time `db:"created_at"` FIXME
+	//UpdatedAt   time.Time `db:"updated_at"` FIXME
+}

internal/models/language.go

@@ -0,0 +1,12 @@
+package models
+
+import "time"
+
+type Language struct {
+	Id              *int32     `db:"id"`
+	Name            *string    `db:"name"`
+	BuildFileHash   *string    `db:"build_file_hash"`
+	ExecuteFileHash *string    `db:"execute_file_hash"`
+	CreatedAt       *time.Time `db:"created_at"`
+	UpdatedAt       *time.Time `db:"updated_at"`
+}

internal/models/problem.go

@@ -0,0 +1,13 @@
+package models
+
+import "time"
+
+type Problem struct {
+	Id          *int32     `db:"id"`
+	Name        *string    `db:"name"`
+	Description *string    `db:"description"`
+	TimeLimit   *int32     `db:"time_limit"`
+	MemoryLimit *int32     `db:"memory_limit"`
+	CreatedAt   *time.Time `db:"created_at"`
+	UpdatedAt   *time.Time `db:"updated_at"`
+}

internal/models/role.go

@@ -0,0 +1,44 @@
+package models
+
+import "git.sch9.ru/new_gate/ms-tester/internal/lib"
+
+type Role int32
+
+const (
+	RoleSpectator   Role = 0
+	RoleParticipant Role = 1
+	RoleModerator   Role = 2
+	RoleAdmin       Role = 3
+)
+
+func (role Role) IsAdmin() bool {
+	return role == RoleAdmin
+}
+
+func (role Role) IsModerator() bool {
+	return role == RoleModerator
+}
+
+func (role Role) IsParticipant() bool {
+	return role == RoleParticipant
+}
+
+func (role Role) IsSpectator() bool {
+	return role == RoleSpectator
+}
+
+func (role Role) AtLeast(other Role) bool {
+	return role >= other
+}
+
+func (role Role) AtMost(other Role) bool {
+	return role <= other
+}
+
+func (role Role) Valid() error {
+	switch role {
+	case RoleSpectator, RoleParticipant, RoleModerator, RoleAdmin:
+		return nil
+	}
+	return lib.ErrBadRole
+}

internal/models/solution.go

@@ -0,0 +1,14 @@
+package models
+
+import "time"
+
+type Solution struct {
+	Id            *int32     `db:"id"`
+	ParticipantId *int32     `db:"participant_id"`
+	ProblemId     *int32     `db:"problem_id"`
+	LanguageId    *int32     `db:"language_id"`
+	ContestId     *int32     `db:"contest_id"`
+	SolutionHash  *string    `db:"solution_hash"`
+	Result        *int32     `db:"result"`
+	CreatedAt     *time.Time `db:"created_at"`
+}