add postgresql interface
printout psql connection data
rename connection hooks
Trusty PostgreSQL connection hook
remove postgresql from charm and fix typo for starting
remove comments
add missing library
/home is not ~ sweet ~
fix typos
merge master and fix symlinks
Fixed PostgreSQL install issues

Fixed:
- Renaming bug for pgsql relation in hooks
- Install postgresclient for createdb command
- Remove optional HAProxy service name for now
- Use pybossa as database name
- Also search and replace postgresql config line in alembic.ini

TODO:
- Precise version is broken
- Documentation
small typo
remove precise version

The precise charm version requires extra testing and Ubuntu 14.04 Trusty Tahr
seems to run very well.
update docs