API Increased support to 9.2

Anything older than 9.3 is unsupported by Postgres: https://www.postgresql.org/support/versioning/.
I don't think we should claim support in our module for unsupported versions,
particularly if we don't have CI on them.

Since we're *only* running CI on 9.2 at the moment, that's the safe claim
for our module support, even though it's already unsupported by Postgres.
See https://docs.travis-ci.com/user/database-setup/#using-a-different-postgresql-version

I'll raise a separate ticket about testing and supporting newer versions,
it's out of scope for this PR.

README.md

@@ -10,20 +10,37 @@
 ## Requirements
 
 * SilverStripe 4.0
-* PostgreSQL 8.3.x or greater must be installed
+* PostgreSQL >=9.2
-* PostgreSQL <8.3.0 may work if T-Search is manually installed
+* Note: PostgreSQL 10 has not been tested
-*  Known to work on OS X Leopard, Windows Server 2008 R2 and Linux
 
 ## Installation
 
- 1. Install via composer `composer require silverstripe/postgresql` or extract the contents
+```
-    so they reside as a `postgresql` directory inside your SilverStripe project code
+composer require silverstripe/postgresql
- 2. Open the installer by browsing to install.php, e.g. http://localhost/silverstripe/install.php
+```
- 3. Select PostgreSQL in the database list and enter your database details
+
+## Configuration
+
+### Environment file
+
+Add the following settings to your `.env` file:
+
+```
+SS_DATABASE_CLASS=PostgreSQLDatabase
+SS_DATABASE_USERNAME=
+SS_DATABASE_PASSWORD=
+```
+
+See [environment variables](https://docs.silverstripe.org/en/4/getting_started/environment_management) for more details. Note that a database will automatically be created via `dev/build`.
+
+### Through the installer
+
+Open the installer by browsing to install.php, e.g. http://localhost/install.php
+Select PostgreSQL in the database list and enter your database details
 
 ## Usage Overview
 
-See docs/en for more information about configuring the module.
+See [docs/en](docs/en/README.md) for more information about configuring the module.
 	
 ## Known issues
 

docs/en/README.md

@@ -1,86 +1,5 @@
 # PostgreSQL Database Module
 
-SilverStripe now has tentative support for PostgreSQL ('Postgres').
-
-## Requirements
-
-SilverStripe 2.4.0 or greater. (PostgreSQL support is NOT available 
-in 2.3.).
-
-SilverStripe supports Postgres versions 8.3.x, 8.4.x and onwards. 
-Postgres 8.3.0 launched in February 2008, so SilverStripe has a fairly 
-modern but not bleeding edge Postgres version requirement.
-
-Support for 8.2.x is theoretically possible if you're willing to manually 
-install T-search. 8.2.x has not been tested either, so there may be other 
-compatibility issues. The EnterpriseDB versions of Postgres also work, if 
-you'd prefer a tuned version.
-
-## Installation
-
-You have three options to install PostgreSQL support with SilverStripe. 
-
-### Option 1 - Installer
-
-The first option is to use the installer. However, this is currently only 
-supported since SilverStripe 2.4.0 beta2 (or using the daily builds).
-
-1. Set up SilverStripe somewhere where you can start the installer - you 
-should only see one database “MySQL” to install with.
-2. Download a copy of the “postgresql” module from here: 
-http://silverstripe.org/postgresql-module
-3. Extract the archive you downloaded. Rename the directory from 
-“postgresql-trunk-rxxxx” to “postgresql” and copy it into the SilverStripe 
-directory you just set up
-4. Open the installer once again, and a new option “PostgreSQL” should appear. 
-You can now proceed through the installation without having to change any code.
-
-### Option 2 - Manual
-
-The second option is to setup PostgreSQL support manually. This can be achieved 
-by following these instructions:
-
-1. Set up a fresh working copy of SilverStripe
-2. Download a copy of the “postgresql” module from here: http://silverstripe.org/postgresql-module
-3. Extract the archive you downloaded. Rename the directory from 
-“postgresql-trunk-rxxxx” to “postgresql” and copy it into the SilverStripe 
-directory you just set up.
-4. Open up your mysite/_config.php file and add (or update) the $databaseConfig 
-array like so:
-
-> $databaseConfig = array(
->	'type' => 'PostgreSQLDatabase',
->	'server' => '[server address e.g. localhost]',
->	'username' => 'postgres',
->	'password' => 'mypassword',
->	'database' => 'SS_mysite'
-> );
-
-Finally, visit dev/build so that SilverStripe can build the database schema and 
-default records.
-
-### Option 3 - Environment file
-
-Finally, the third option is to change your environment to point to 
-PostgreSQLDatabase as a database class. Do this if you're currently using an
- _ss_environment.php file.
-
-1. Download a copy of the “postgresql” module from here: http://silverstripe.org/postgresql-module
-2. Extract the archive you downloaded. Rename the directory from 
-postgresql-trunk-rxxxx” to “postgresql” and copy it into your SS directory
-3. Add the following to your existing _ss_environment.php file:
-
-> define('SS_DATABASE_CLASS', 'PostgreSQLDatabase');
-
-Last steps:
-
-1. Ensure your SS_DATABASE_USERNAME and SS_DATABASE_PASSWORD defines in 
-_ss_environment.php are correct to the PostgreSQL server.
-2. Ensure that your mysite/_config.php file has a database name defined, such 
-as “SS_mysite”.
-3. Visit dev/build so that SilverStripe can build the database schema and 
-default records
-
 ## Features
 
 Here is a quick list of what's different in the Postgres module (a full 
@@ -301,21 +220,3 @@ connection, no matter what you entered in the "Database Name" field during
 installation.
 
 Make sure you have set the "search_path" correct for your database user. 
-
-## Known Issues
-
-All column and table names must be double-quoted.  PostgreSQL automatically 
-lower-cases columns, and your queries will fail if you don't.
-
-Ts_vector columns are not automatically detected by the built-in search filters.  
-That means if you're doing a search through the CMS on a ModelAdmin object, it 
-will use LIKE queries which are very slow.  
-
-If you're writing your own front-end search system, you can specify the columns 
-to use for search purposes, and you get the full benefits of T-Search.
-
-If you are using unsupported modules, there may be instances of MySQL-specific 
-SQL queries which will need to be made database-agnostic where possible.
-
-
-