Add support for keys with ttl (#177)

* ttl support first commit

* imports fix

* put api args correction

* put options added

* upgrade method added

* upgrade log added

* v0 to v1 migration script added

* error assertion added

* temp migration dir fix

Co-authored-by: yash <yash.chandra@grabpay.com>

internal/config/config.go

@@ -13,6 +13,7 @@ type Config struct {
 	MaxValueSize            uint64 `json:"max_value_size"`
 	Sync                    bool   `json:"sync"`
 	AutoRecovery            bool   `json:"autorecovery"`
+	DBVersion               uint32 `json:"db_version"`
 	DirFileModeBeforeUmask  os.FileMode
 	FileFileModeBeforeUmask os.FileMode
 }