Second commit

added few test, first api to add book

go.mod

@@ -6,6 +6,7 @@ require (
 	github.com/gin-contrib/cors v1.7.6
 	github.com/gin-gonic/gin v1.10.1
 	github.com/pelletier/go-toml v1.9.5
+	github.com/stretchr/testify v1.10.0
 	gorm.io/driver/sqlite v1.6.0
 	gorm.io/gorm v1.31.0
 )
@@ -15,6 +16,7 @@ require (
 	github.com/bytedance/sonic v1.14.1 // indirect
 	github.com/bytedance/sonic/loader v0.3.0 // indirect
 	github.com/cloudwego/base64x v0.1.6 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/gabriel-vasile/mimetype v1.4.10 // indirect
 	github.com/gin-contrib/sse v1.1.0 // indirect
 	github.com/go-playground/locales v0.14.1 // indirect
@@ -32,6 +34,7 @@ require (
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/pelletier/go-toml/v2 v2.2.4 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
 	github.com/ugorji/go/codec v1.3.0 // indirect
 	golang.org/x/arch v0.21.0 // indirect