Add basic Matrix puppeting support

May contain bugs.
EDUs from /sync are not yet handled.

database/upgrades/2019-05-23-puppet-custom-mxid-columns.go

@@ -0,0 +1,23 @@
+package upgrades
+
+import (
+	"database/sql"
+)
+
+func init() {
+	upgrades[5] = upgrade{"Add columns to store custom puppet info", func(dialect Dialect, tx *sql.Tx, db *sql.DB) error {
+		_, err := tx.Exec(`ALTER TABLE puppet ADD COLUMN custom_mxid VARCHAR(255)`)
+		if err != nil {
+			return err
+		}
+		_, err = tx.Exec(`ALTER TABLE puppet ADD COLUMN access_token VARCHAR(1023)`)
+		if err != nil {
+			return err
+		}
+		_, err = tx.Exec(`ALTER TABLE puppet ADD COLUMN next_batch VARCHAR(255)`)
+		if err != nil {
+			return err
+		}
+		return nil
+	}}
+}

database/upgrades/upgrades.go

@@ -22,7 +22,9 @@ type upgrade struct {
 	fn upgradeFunc
 }
 
-var upgrades [5]upgrade
+const NumberOfUpgrades = 6
+
+var upgrades [NumberOfUpgrades]upgrade
 
 func getVersion(dialect Dialect, db *sql.DB) (int, error) {
 	_, err := db.Exec("CREATE TABLE IF NOT EXISTS version (version INTEGER)")
@@ -63,7 +65,7 @@ func Run(log log.Logger, dialectName string, db *sql.DB) error {
 		return err
 	}
 
-	log.Infofln("Database currently on v%d, latest: v%d", version, len(upgrades))
+	log.Infofln("Database currently on v%d, latest: v%d", version, NumberOfUpgrades)
 	for i, upgrade := range upgrades[version:] {
 		log.Infofln("Upgrading database to v%d: %s", version+i+1, upgrade.message)
 		tx, err := db.Begin()