Update README.md

Author: ddeboer

README.md

@@ -31,18 +31,98 @@ Installation
 ------------
 
 This library is available on [Packagist](http://packagist.org/packages/phpforce/soap-client). 
-The recommended way to install this library is through [Composer](http://getcomposer.org).
+The recommended way to install this library is through [Composer](http://getcomposer.org):
 
-To install it, add the following to your `composer.json`:
+```bash
+$ php composer.phar require phpforce/soap-client dev-master
+```
+
+Usage
+-----
+
+### The client
+
+Use the client to query and manipulate your organisation’s Salesforce data. First construct a client using the builder:
+
+```php
+$builder = new \Phpforce\SoapClient\ClientBuilder(
+  '/path/to/your/salesforce/wsdl/sandbox.enterprise.wsdl.xml'
+  'username',
+  'password',
+  'security_token'
+);
+
+$client = $builder->build();
+```
+
+### SOQL queries
+
+```php
+$result = $client->query('select Name, SystemModstamp from Account limit 5');
+```
+
+This will fetch five accounts from Salesforce and return them as a
+`RecordIterator`. You can now iterate over the results. The account’s
+`SystemModstamp` is returned as a `\DateTime` object:
+
+```php
+foreach ($results as $account) {
+    echo 'Last modified: ' . $account->SystemModstamp->format('Y-m-d H:i:') . "\n";
+}
+```
 
-```JSON
-{
-    "require": {
-        ...
-        "phpforce/soap-client": "dev-master",
-        ...
+### One-to-many relations (subqueries)
+
+Results from [subqueries](http://www.salesforce.com/us/developer/docs/api/Content/sforce_api_calls_soql_select.htm) 
+are themselves returned as record iterators. So:
+
+```php
+$accounts = $client->query(
+    'select Id, (select Id, Name from Contacts) from Account limit 10'
+);
+
+foreach ($accounts as $account) {
+    if (isset($account->Contacts)) {
+        foreach ($account->Contacts as $contact) {
+            echo sprintf("Contact %s has name %s\n", $contact->Id, $contact->Name);
+        }
     }
 }
 ```
 
-And run `$ php composer.phar install`.
+### Fetching large numbers of records
+
+If you issue a query that returns over 2000 records, only the first 2000 records
+will be returned by the Salesforce API. Using the `queryLocator`, you can then
+fetch the following results in batches of 2000. The record iterator does this
+automatically for you:
+
+```php
+$accounts = $client->query('Select Name from Account');
+echo $accounts->count() . ' accounts returned';
+foreach ($accounts as $account) {
+    // This will iterate over the 2000 first accounts, then fetch the next 2000
+    // and iterate over these, etc. In the end, all your organisations’s accounts
+    // will be iterated over.
+}
+```
+
+### Logging
+
+To enable logging for the client, call `withLog()` on the builder. For instance when using [Monolog](https://github.com/Seldaek/monolog):
+
+```php
+$log = new \Monolog\Logger('name');  
+$log->pushHandler(new \Monolog\Handler\StreamHandler('path/to/your.log'));
+
+$builder = new \Phpforce\SoapClient\ClientBuilder(
+  '/path/to/your/salesforce/wsdl/sandbox.enterprise.wsdl.xml'
+  'username',
+  'password',
+  'security_token'
+);
+$client = $builder->withLog($log)
+  ->build();
+```
+
+All requests to the Salesforce API, as well as the responses and any errors that it returns, will now be logged.