readme: tablename example wasn't clear enough

Improve TableName usage explanation on README

README.md

@@ -77,7 +77,7 @@ func main() {
 ```
 
 Notes on examples above:
-- Migrator creates/manages a table named `migrations` to keep track of the applied versions. However, if want to customize the table name `TableName("my_migrations")` can be also used.  
+- Migrator creates/manages a table named `migrations` to keep track of the applied versions. However, if want to customize the table name `migrator.TableName("my_migrations")` can be passed to `migrator.New` function as an additional option. 
 
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