Break out structs and errors into separate files in storage package

storage/errors.go

@@ -0,0 +1,6 @@
+package storage
+
+import "errors"
+
+// ErrNotFound is the default error message when data is not found.
+var ErrNotFound = errors.New("not found")

storage/record.go

@@ -0,0 +1,7 @@
+package storage
+
+// Record provides a standard way to refer to a shortened URL.
+type Record struct {
+	UID []byte
+	URL []byte
+}

storage/store.go

@@ -1,10 +1,5 @@
 package storage
 
-import "errors"
-
-// ErrNotFound is the default error message when data is not found.
-var ErrNotFound = errors.New("not found")
-
 // Store defines a standard interface for storage
 type Store interface {
 	Close() error
@@ -15,9 +10,3 @@ type Store interface {
 	DeleteByURL(URL []byte) (*Record, error)
 	NextSequence() (int, error)
 }
-
-// Record provides a standard way to refer to a shortened URL.
-type Record struct {
-	UID []byte
-	URL []byte
-}