Migration error with rake db:migraiton and citygram - Boxen setup

gistfile1.txt

Attempting to setup Citygram, with a boxen setup.  The rake:db create command works, but migrations fail with the below error.

bundle exec rake db:migrate DATABASE_URL=postgres://localhost:15432/citygram_development
rake aborted!
Sequel::DatabaseError: PG::UndefinedFile: ERROR:  could not open extension control file "/opt/boxen/homebrew/Cellar/postgresql/9.3.2-boxen/share/postgresql/extension/postgis.control": No such file or directory
/Users/masonpackard/src/citygram/db/migrations/001_enable_postgis_extension.rb:3:in `block (2 levels) in <top (required)>'
/Users/masonpackard/src/citygram/lib/database_helper.rb:60:in `migrate_db'
/Users/masonpackard/src/citygram/lib/tasks/database.rake:26:in `block (2 levels) in <top (required)>'
PG::UndefinedFile: ERROR:  could not open extension control file "/opt/boxen/homebrew/Cellar/postgresql/9.3.2-boxen/share/postgresql/extension/postgis.control": No such file or directory
/Users/masonpackard/src/citygram/db/migrations/001_enable_postgis_extension.rb:3:in `block (2 levels) in <top (required)>'
/Users/masonpackard/src/citygram/lib/database_helper.rb:60:in `migrate_db'
/Users/masonpackard/src/citygram/lib/tasks/database.rake:26:in `block (2 levels) in <top (required)>'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)