Update docs and examples (#3)

Author: vearutop

README.md

@@ -14,16 +14,18 @@ for [`github.com/cucumber/godog`](https://github.com/cucumber/godog).
 
 Databases instances should be configured with `Manager.Instances`.
 
-```go
-dbm := dbsteps.Manager{}
-
-dbm.Instances = map[string]dbsteps.Instance{
-    "my_db": {
-        Storage: storage,
-        Tables: map[string]interface{}{
-            "my_table":           new(repository.MyRow),
-            "my_another_table":   new(repository.MyAnotherRow),
-        },
+```
+// Initialize database manager with storage and table rows references.
+dbm := dbsteps.NewManager()
+dbm.Instances["my_db"] = dbsteps.Instance{
+    Storage: storage,
+    Tables: map[string]interface{}{
+        "my_table":         new(repository.MyRow),
+        "my_another_table": new(repository.MyAnotherRow),
+    },
+    // Optionally configure statements to execute after deleting rows from table.
+    PostCleanup: map[string][]string{
+        "my_table": {"ALTER SEQUENCE my_table_id_seq RESTART"},
     },
 }
 ```
@@ -53,6 +55,7 @@ tableMapper.Decoder.RegisterFunc(func(s string) (interface{}, error) {
     if err != nil {
         return nil, err
     }
+	
     return m, err
 }, repository.Meta{})
 
@@ -62,9 +65,8 @@ tableMapper.Decoder.RegisterFunc(func(s string) (interface{}, error) {
 }, pq.StringArray{})
 
 // Create database manager with custom mapper.
-dbm := dbsteps.Manager{
-    TableMapper: tableMapper,
-}
+dbm := dbsteps.NewManager()
+dbm.TableMapper = tableMapper
 ```
 
 ## Step Definitions

example_test.go

@@ -0,0 +1,62 @@
+package dbsteps_test
+
+import (
+	"encoding/json"
+
+	"github.com/bool64/sqluct"
+	"github.com/godogx/dbsteps"
+)
+
+func ExampleNewManager() {
+	// Set up a storage adapter for your database connection.
+	var storage *sqluct.Storage
+
+	// Define database row structures in your repository packages.
+	type MyRow struct {
+		Foo string `db:"foo"`
+	}
+
+	type MyAnotherRow struct {
+		Bar int     `db:"bar"`
+		Baz float64 `db:"baz"`
+	}
+
+	// ...........
+
+	// Initialize database manager with storage and table rows references.
+	dbm := dbsteps.NewManager()
+	dbm.Instances["my_db"] = dbsteps.Instance{
+		Storage: storage,
+		Tables: map[string]interface{}{
+			"my_table":         new(MyRow),
+			"my_another_table": new(MyAnotherRow),
+		},
+		// Optionally configure statements to execute after deleting rows from table.
+		PostCleanup: map[string][]string{
+			"my_table": {"ALTER SEQUENCE my_table_id_seq RESTART"},
+		},
+	}
+}
+
+func ExampleNewTableMapper() {
+	type jsonData struct {
+		Foo string `json:"foo"`
+	}
+
+	tableMapper := dbsteps.NewTableMapper()
+
+	// Apply JSON decoding to a particular type.
+	tableMapper.Decoder.RegisterFunc(func(s string) (interface{}, error) {
+		data := jsonData{}
+		err := json.Unmarshal([]byte(s), &data)
+		if err != nil {
+			return nil, err
+		}
+
+		return data, err
+	}, jsonData{})
+
+	// Create database manager with custom mapper.
+	dbm := dbsteps.NewManager()
+	dbm.TableMapper = tableMapper
+}

go.mod

@@ -8,7 +8,7 @@ require (
 	github.com/bool64/dev v0.2.5
 	github.com/bool64/shared v0.1.4
 	github.com/bool64/sqluct v0.1.9
-	github.com/cucumber/godog v0.12.3
+	github.com/cucumber/godog v0.12.4
 	github.com/godogx/resource v0.1.0
 	github.com/jmoiron/sqlx v1.3.4
 	github.com/stretchr/testify v1.7.0

go.sum

@@ -49,8 +49,9 @@ github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f/go.mod h1:E3G3o1h8I7cfc
 github.com/cpuguy83/go-md2man/v2 v2.0.0/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
 github.com/cucumber/gherkin-go/v19 v19.0.3 h1:mMSKu1077ffLbTJULUfM5HPokgeBcIGboyeNUof1MdE=
 github.com/cucumber/gherkin-go/v19 v19.0.3/go.mod h1:jY/NP6jUtRSArQQJ5h1FXOUgk5fZK24qtE7vKi776Vw=
-github.com/cucumber/godog v0.12.3 h1:nBshklqcWho/joTFtSBfyD4KYkvftwwf0r0XpX6ajNU=
 github.com/cucumber/godog v0.12.3/go.mod h1:u6SD7IXC49dLpPN35kal0oYEjsXZWee4pW6Tm9t5pIc=
+github.com/cucumber/godog v0.12.4 h1:m+vQaDztkpwpmkBIX6jlwNFJiuCMkPjz5jkrUq4SIlM=
+github.com/cucumber/godog v0.12.4/go.mod h1:u6SD7IXC49dLpPN35kal0oYEjsXZWee4pW6Tm9t5pIc=
 github.com/cucumber/messages-go/v16 v16.0.0/go.mod h1:EJcyR5Mm5ZuDsKJnT2N9KRnBK30BGjtYotDKpwQ0v6g=
 github.com/cucumber/messages-go/v16 v16.0.1 h1:fvkpwsLgnIm0qugftrw2YwNlio+ABe2Iu94Ap8GMYIY=
 github.com/cucumber/messages-go/v16 v16.0.1/go.mod h1:EJcyR5Mm5ZuDsKJnT2N9KRnBK30BGjtYotDKpwQ0v6g=

manager.go

@@ -224,7 +224,7 @@ func (m *Manager) registerAssertions(s *godog.ScenarioContext) {
 		})
 }
 
-// NewManager initializes instance of database Manager.
+// NewManager creates an instance of database Manager.
 func NewManager() *Manager {
 	return &Manager{
 		TableMapper: NewTableMapper(),
@@ -235,6 +235,8 @@ func NewManager() *Manager {
 }
 
 // Manager owns database connections.
+//
+// Please use NewManager to create an instance.
 type Manager struct {
 	lock *resource.Lock