PLEASE MAKE SURE YOU BACKUP YOUR PUBLIC SCHEMA !

Steps:

1. Open up pgAdmin III and connect to PostgreSQL.
2. Select desired database and click on schemas
3. Open up SQL Editor
4. Open & execute public_schema.sql
5. Open & execute public_data.sql
6. Open rename_schema.sql and replace `new_schema_name` with the name you want, then execute the query

Files can be found here: PostGIS Enabled Schema