Add Primary Key to Topic and RepoTopic (#12639)

Add a primary key to Topic and RepoTopic tables

Fix #8920

Signed-off-by: Andrew Thornton <art27@cantab.net>

models/topic.go

@@ -25,7 +25,7 @@ var topicPattern = regexp.MustCompile(`^[a-z0-9][a-z0-9-]*$`)
 
 // Topic represents a topic of repositories
 type Topic struct {
-	ID          int64
+	ID          int64  `xorm:"pk autoincr"`
 	Name        string `xorm:"UNIQUE VARCHAR(25)"`
 	RepoCount   int
 	CreatedUnix timeutil.TimeStamp `xorm:"INDEX created"`
@@ -34,8 +34,8 @@ type Topic struct {
 
 // RepoTopic represents associated repositories and topics
 type RepoTopic struct {
-	RepoID  int64 `xorm:"UNIQUE(s)"`
-	TopicID int64 `xorm:"UNIQUE(s)"`
+	RepoID  int64 `xorm:"pk"`
+	TopicID int64 `xorm:"pk"`
 }
 
 // ErrTopicNotExist represents an error that a topic is not exist