Add context to fluentd formatter

src/Monolog/Formatter/FluentdFormatter.php

@@ -62,6 +62,7 @@ class FluentdFormatter implements FormatterInterface
 
         $message = array(
             'message' => $record['message'],
+            'context' => $record['context'],
             'extra' => $record['extra'],
         );
 

tests/Monolog/Formatter/FluentdFormatterTest.php

@@ -40,7 +40,7 @@ class FluentdFormatterTest extends TestCase
 
         $formatter = new FluentdFormatter();
         $this->assertEquals(
-            '["test",0,{"message":"test","extra":[],"level":300,"level_name":"WARNING"}]',
+            '["test",0,{"message":"test","context":[],"extra":[],"level":300,"level_name":"WARNING"}]',
             $formatter->format($record)
         );
     }
@@ -55,7 +55,7 @@ class FluentdFormatterTest extends TestCase
 
         $formatter = new FluentdFormatter(true);
         $this->assertEquals(
-            '["test.error",0,{"message":"test","extra":[]}]',
+            '["test.error",0,{"message":"test","context":[],"extra":[]}]',
             $formatter->format($record)
         );
     }