Add a context field to symbol objects

Summary:
See T1602.

This is just the minimal functional patch; the scripts will continue
working because of the `DEFAULT ''`.

Test Plan:
Can't fully test this until I get more code working, but
nothing broke horribly yet.

Reviewers: epriestley

Reviewed By: epriestley

CC: nh, aran, Korvin

Maniphest Tasks: T1602

Differential Revision: https://secure.phabricator.com/D3147

resources/sql/patches/symbolcontexts.sql

@@ -0,0 +1,3 @@
+ALTER TABLE {$NAMESPACE}_repository.repository_symbol
+  ADD symbolContext varchar(128) COLLATE utf8_general_ci NOT NULL DEFAULT ''
+  AFTER arcanistProjectID;

src/applications/repository/storage/PhabricatorRepositorySymbol.php

@@ -27,6 +27,7 @@
 final class PhabricatorRepositorySymbol extends PhabricatorRepositoryDAO {
 
   protected $arcanistProjectID;
+  protected $symbolContext;
   protected $symbolName;
   protected $symbolType;
   protected $symbolLanguage;

src/infrastructure/storage/patch/PhabricatorBuiltinPatchList.php

@@ -936,6 +936,10 @@ final class PhabricatorBuiltinPatchList extends PhabricatorSQLPatchList {
         'type'    => 'sql',
         'name'    => $this->getPatchPath('daemonstatus.sql'),
       ),
+      'symbolcontexts.sql' => array(
+        'type'    => 'sql',
+        'name'    => $this->getPatchPath('symbolcontexts.sql'),
+      ),
     );
   }