Add support for database migrations (#1416)

* Add support for database migrations

Closes #1246

This PR does NOT add any migrations as an example. I have
manually tested that the library works with SQL and Go based
upgrades correctly. Documentation should be sufficient for
devs to add migrations.

* Clarifications

* Linting

cmd/goose/main.go

@@ -0,0 +1,98 @@
+// This is custom goose binary
+
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"os"
+
+	// Example complex Go migration import:
+	// _ "github.com/matrix-org/dendrite/serverkeyapi/storage/postgres/deltas"
+	"github.com/pressly/goose"
+
+	_ "github.com/lib/pq"
+	_ "github.com/mattn/go-sqlite3"
+)
+
+var (
+	flags = flag.NewFlagSet("goose", flag.ExitOnError)
+	dir   = flags.String("dir", ".", "directory with migration files")
+)
+
+func main() {
+	err := flags.Parse(os.Args[1:])
+	if err != nil {
+		panic(err.Error())
+	}
+	args := flags.Args()
+
+	if len(args) < 3 {
+		fmt.Println(
+			`Usage: goose [OPTIONS] DRIVER DBSTRING COMMAND
+
+Drivers:
+    postgres
+    sqlite3
+
+Examples:
+    goose -d roomserver/storage/sqlite3/deltas sqlite3 ./roomserver.db status
+    goose -d roomserver/storage/sqlite3/deltas sqlite3 ./roomserver.db up
+
+    goose -d roomserver/storage/postgres/deltas postgres "user=dendrite dbname=dendrite sslmode=disable" status
+
+Options:
+
+  -dir string
+    	directory with migration files (default ".")
+  -table string
+    	migrations table name (default "goose_db_version")
+  -h	print help
+  -v	enable verbose mode
+  -version
+    	print version
+
+Commands:
+    up                   Migrate the DB to the most recent version available
+    up-by-one            Migrate the DB up by 1
+    up-to VERSION        Migrate the DB to a specific VERSION
+    down                 Roll back the version by 1
+    down-to VERSION      Roll back to a specific VERSION
+    redo                 Re-run the latest migration
+    reset                Roll back all migrations
+    status               Dump the migration status for the current DB
+    version              Print the current version of the database
+    create NAME [sql|go] Creates new migration file with the current timestamp
+    fix                  Apply sequential ordering to migrations`,
+		)
+		return
+	}
+
+	engine := args[0]
+	if engine != "sqlite3" && engine != "postgres" {
+		fmt.Println("engine must be one of 'sqlite3' or 'postgres'")
+		return
+	}
+	dbstring, command := args[1], args[2]
+
+	db, err := goose.OpenDBWithDriver(engine, dbstring)
+	if err != nil {
+		log.Fatalf("goose: failed to open DB: %v\n", err)
+	}
+
+	defer func() {
+		if err := db.Close(); err != nil {
+			log.Fatalf("goose: failed to close DB: %v\n", err)
+		}
+	}()
+
+	arguments := []string{}
+	if len(args) > 3 {
+		arguments = append(arguments, args[3:]...)
+	}
+
+	if err := goose.Run(command, db, *dir, arguments...); err != nil {
+		log.Fatalf("goose %v: %v", command, err)
+	}
+}