Is necessary to create a new table in this context?
If the same ProjectDescription can be used by multiple different Templates then you'll need a third table, as a linking table, for the many-to-many relationship between the two entities. Otherwise you'd be forced to store duplicate rows in ProjectDescription which is bad design from a Normalization standpoint.
The linking table would be simple and just store template_id and projectdescription_id, and the primary key would be a composite key on both those fields.