feat: system pronouns (#429)

PluralKit.Core/Database/Migrations/28.sql

@@ -0,0 +1,7 @@
+-- schema version 28
+-- system pronouns
+
+alter table systems add column pronouns text;
+alter table systems add column pronoun_privacy integer check (pronoun_privacy in (1, 2)) not null default 1;
+
+update info set schema_version = 28;

PluralKit.Core/Database/Utils/DatabaseMigrator.cs

@@ -9,7 +9,7 @@ namespace PluralKit.Core;
 internal class DatabaseMigrator
 {
     private const string RootPath = "PluralKit.Core.Database"; // "resource path" root for SQL files
-    private const int TargetSchemaVersion = 27;
+    private const int TargetSchemaVersion = 28;
     private readonly ILogger _logger;
 
     public DatabaseMigrator(ILogger logger)