Enabling hstore for new postgresql 9.1 and rails 3 install on ubuntu 12.04

gistfile1.sh

RAILS_ENV=production rake db:setup
# produces the error below.....hmmm.....it's a no-worky
psql:/yourprojectpath/yourproject/db/structure.sql:29: ERROR:  could not open extension control file "/usr/share/postgresql/9.1/extension/hstore.control": No such file or directory

# hstore postgresql extension needs to be installed, so....
sudo apt-get install postgresql-contrib

# now your extension should be available to enable so log in with psql
psql -d yourproject_production -U yourdbuser -W

# in the psql shell
CREATE EXTENSION hstore;
\q

# now you're golden, may need to clean up and re-run
RAILS_ENV=production rake db:drop
RAILS_ENV=production rake db:setup

I'm using Rails 5.0.2 and Postgres 9.5 on Ubuntu 16.04.3 LTS and what worked for me are the next two options:

First one:

- Install the extension with:
    sudo apt-get install postgresql-contrib
- Enable the extension in the corresponding Data Base:
    sudo su postgres -c "psql my_db_production -c 'CREATE EXTENSION hstore;'"

Second one:

- Install the extension with:
    sudo apt-get install postgresql-contrib
- Login as super user in Postgres
    sudo su - postgres
- Enter to your Data Base console:
    psql -d my_db_production -W
- In the psql shell run:
    CREATE EXTENSION hstore;
- Exit
    \q 

Now migrations run with out any error!
I hope it could be useful!