Add information on how to run integration tests

Closes #525
Change CLI config logic to support usage without environments

Scenario 1: Environment is defined via --env or NODE_ENV
* config is config[environment]

Scenario 2: Environment is undefined but config.development is an object
* config is config.development

Scenario 3: No environment and no config.development
* config is config

Also logs out the environment in use for scenarios 1 and 2
Add documentation for using CLI and knexfile without environments
Sample seed files now correctly return Promises tgriesser/knex#391
Updated seed file documentation
Merge pull request #528 from nsantorello/master

* Updated seed file documentation
* Sample seed files now correctly return Promises tgriesser/knex#391
support creating and dropping extensions in postgresql
Merge pull request #540 from tkellen/extensions

support creating and dropping extensions in postgresql
Merge pull request #527 from tgriesser/cli-without-env

CLI support for knexfiles that do not provide environment keys
Add note about bigint types to schema
Add note about bigint in Postgres with count
Merge branch 'bigint'

* bigint:
  Add note about bigint in Postgres with count
  Add note about bigint types to schema

Closes #548
Added sqlite3 dialect version of whereRaw/andWhereRaw

* SQLite uses integers, not booleans
* whereIn/whereNotIn with empty array uses a boolean
* Closes #477
Add POSIX operator support for Postgres

Closes #562, Closes #561
Use chai throw assertions instead of manual try catch
typo orWhereNull
Merge pull request #571 from strathausen/patch-2

typo orWhereNull
support for nested having
add havingWrapped to methods
Merge pull request #572 from PhilWaldmann/master

add nested having support