ADD: User authentication

* User Authentication Implementation
* Rename file to conform to fileformat `sqlite3_*_omit.go`
* Updated sqlite3-binding.* with new upgrade tool
* Add: callbackRetNil required for error type return because of adding `RegisterFunc`s directly on the connection.
* Add: TestCreateAuthDatabase

sqlite3_opt_userauth_test.go

@@ -0,0 +1,39 @@
+// Copyright (C) 2018 G.J.R. Timmer <gjr.timmer@gmail.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+
+// +build sqlite_userauth
+
+package sqlite3
+
+import (
+	"database/sql"
+	"fmt"
+	"testing"
+)
+
+func TestCreateAuthDatabase(t *testing.T) {
+	tempFilename := TempFilename(t)
+	fmt.Println(tempFilename) // debug
+	//defer os.Remove(tempFilename) // Disable for debug
+
+	db, err := sql.Open("sqlite3", "file:"+tempFilename+"?_auth&_auth_user=admin&_auth_pass=admin")
+	if err != nil {
+		t.Fatal("Failed to open database:", err)
+	}
+	defer db.Close()
+
+	var i int64
+	err = db.QueryRow("SELECT count(type) FROM sqlite_master WHERE type='table' AND name='sqlite_user';").Scan(&i)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Logf("sqlite_user exists: %d", i)
+
+	_, err = db.Exec("SELECT auth_user_add('test', 'test', false);", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+}