docs: add readme, benchmark results and reverse-direction config

Document the tool with a comprehensive README, publish benchmark results, and ship a config-reverse.yaml for the postgres to mssql direction.

cmd/go_migrate/main.go

@@ -9,6 +9,7 @@ import (
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/azure"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/config"
 	dbwrapper "git.ksdemosapps.com/kylesoda/go-migrate/internal/app/db-wrapper"
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/etl"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/etl/extractors"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/etl/loaders"
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/etl/table_analyzers"
@@ -17,6 +18,13 @@ import (
 	"golang.org/x/sync/errgroup"
 )
 
+func newTableAnalyzer(db dbwrapper.DbWrapper) etl.TableAnalyzer {
+	if db.GetDialect() == "postgres" {
+		return table_analyzers.NewPostgresTableAnalyzer(db)
+	}
+	return table_analyzers.NewMssqlTableAnalyzer(db)
+}
+
 func main() {
 	configureLog()
 	checkExpiry()
@@ -163,8 +171,8 @@ func processMigrationJobs(
 	chJobs := make(chan config.Job, len(jobs))
 	var wgJobs sync.WaitGroup
 
-	sourceTableAnalyzer := table_analyzers.NewMssqlTableAnalyzer(sourceDb)
-	targetTableAnalyzer := table_analyzers.NewPostgresTableAnalyzer(targetDb)
+	sourceTableAnalyzer := newTableAnalyzer(sourceDb)
+	targetTableAnalyzer := newTableAnalyzer(targetDb)
 	extractor := extractors.NewExtractor(sourceDb)
 	loader := loaders.NewGenericLoader(targetDb)
 
@@ -181,6 +189,7 @@ func processMigrationJobs(
 					azureClient,
 					loader,
 					job,
+					sourceDb.GetDialect(),
 					targetDb.GetDialect(),
 				)
 

cmd/go_migrate/process.go

@@ -46,9 +46,15 @@ func processMigrationJob(
 	azureClient *azure.Client,
 	loader loaders.GenericLoader,
 	job config.Job,
+	sourceDbType string,
 	targetDbType string,
 ) models.JobResult {
-	transformer := transformers.NewMssqlTransformer(job.ToStorage, job.SourceTable, azureClient)
+	var transformer etl.Transformer
+	if sourceDbType == "postgres" {
+		transformer = transformers.NewPostgresTransformer(job.SourceTable)
+	} else {
+		transformer = transformers.NewMssqlTransformer(job.ToStorage, job.SourceTable, azureClient)
+	}
 	localCtx, cancel := context.WithCancel(ctx)
 	defer cancel()