postgres install and develop applications on MAC OSX with rails

pgsql_workflow.sh

# first install pgsql with home brew 
brew install postgresql

# at this point, you need to be sure you have /usr/local/bin before /usr/bin on your $PATH

# to see, run:
brew doctor

# if doctor does not complain about this issue you can pass this step.
# prepend /usr/local/bin to your PATH in your ~/.bash_profile
#
# PATH=/usr/local/bin:$PATH

# then reload your terminal, 
## either restarting it 

## or entering source command:
source ~/.bash_profile


# then fix some MAC OSX related variables to work with initdb
## if you do want that variables to be persistent, then add them to /etc/sysctl.conf
sudo sysctl -w kern.sysv.shmall=65536
sudo sysctl -w kern.sysv.shmmax=16777216

# after that initialize main db
initdb /usr/local/var/postgres -E utf8

# then start psql
pg_ctl -D /usr/local/var/postgres -l /usr/local/var/postgres/server.log start

## at any point you can stop pg by entering;
# pg_ctl -D /usr/local/var/postgres stop -s -m fast

# create your rails application by specifying database as psql  
## this process will add boilerplate config/database.yml file 
## with postgres role specific to your rails application.
###  ...
###  development:
###    adapter: postgresql
###    encoding: unicode
###    database: app_name_development
###    pool: 5
###    username: app_name
###    password:
###  ...
rails new app_name -d postgresql

# change directory to your application folder
cd app_name

# now add your app role to pgsql

## first login
psql -d postgres

## when you are inside of postgres=#,
## add your role with login and createdb permissions
# postgres=# create role app_name login createdb;

# it will be better if we reinstall all related pg gems
gem uninstall pg  # uninstall all
bundle

## finally, run rake task to create initial database
rake db:create:all