Proper DB migration

migration/thumbnails.3.cr

@@ -0,0 +1,20 @@
+class CreateThumbnails < MG::Base
+  def up : String
+    <<-SQL
+    CREATE TABLE IF NOT EXISTS thumbnails (
+      id TEXT NOT NULL,
+      data BLOB NOT NULL,
+      filename TEXT NOT NULL,
+      mime TEXT NOT NULL,
+      size INTEGER NOT NULL
+    );
+    CREATE UNIQUE INDEX IF NOT EXISTS tn_index ON thumbnails (id);
+    SQL
+  end
+
+  def down : String
+    <<-SQL
+    DROP TABLE thumbnails;
+    SQL
+  end
+end