Postgres supports different indexing methods (https://www.postgresql.org/docs/9.6/static/sql-createindex.html):
The name of the index method to be used. Choices are btree, hash, gist, spgist, gin, and brin. The default method is btree.
Non-default index method is very important for index DDL. The parts in bold are missing from DataGrip-generated DDL.
CREATE INDEX ssd_wos_auth_source_id_index
ON wos_authors USING hash (source_id) TABLESPACE ernie_index_tbs;