Update README to explain Heroku support for persistent schema's.

Since Rails 4.1 the database.yml isn't completely overwritten which
enables an easy solution for persistent schema's on Heroku. See Heroku
changelog item: https://devcenter.heroku.com/changelog-items/426
Merge pull request #140 from stefanroex/update_readme_heroku

Update README to explain Heroku support for persistent schema's.
Update README for shared extensions schema

https://github.com/influitive/apartment/issues/135
Formatting
Use same logic as postgres adapter in postgis

This adds support for use_schemas = true as well as use_sql = true when
using the postgis adapter.
Merge pull request #150 from fphilipe/fix-postgis-adapter

Use same logic as postgres adapter in postgis
Merge pull request #141 from danelowe/development

Update README for shared extensions schema
add rails4.1 to the Appraisals
generalize rescuable exceptions (needed for ActiveRecord >4.1)
Merge pull request #143 from tarzan/development

Support activerecord 4.1.1 as a dependency
deprecate Apartment::Database in favor of Apartment::Tenant
Fix schema migrations for tenants using sql creation

Remove hardcoded reference to 'bithub_development'
patch versions are probably ok
Post install message for deprecations
release v0.25.0
Update reloader.rb

Database was deprecated in version 0.25.0, but was still used in Apartment::Reloader and is causing many deprecation warnings in the log file.
Update migrator.rb

Database.process still called from Apartment::Migrator - should now be Tenant.process.
Merge pull request #157 from bitencode/development

Update reloader.rb - Looks like a use of Appartment::Database was missed.
Merge pull request #156 from jonsgreen/development

Fix schema migrations for tenants using sql creation
Instruction on how to config postgresql/hstore with apartment on Heroku