Specify collation for Postgres DBs

[sislr]

follows https://github.com/renuo/renuo-cli/pull/287

Tested locally

generated config/database.yml:

default: &default
  adapter: postgresql
  template: template0
  collation: C.UTF-8
  encoding: unicode

DB setup:

test2_development=# SELECT datname, datcollate FROM pg_database where datname = 'test2_development';
      datname      | datcollate
-------------------+------------
 test2_development | C.UTF-8
(1 row)

[sislr]

template0 is required as it fails otherwise with:

PG::InvalidParameterValue: ERROR:  new collation (C.UTF-8) is incompatible with the collation of the template database (C) (PG::InvalidParameterValue)
HINT:  Use the same collation as in the template database, or use template0 as template.

[sislr]

these were outdated anyways