Added the abstract into the template

data.js

@@ -204,6 +204,14 @@ const typst_header = `#import "template/template.typ": *
   document: "{thesis_type.type}",
   lang: "{language.lang}",
   title: (cs: "{thesis_title.cs}", en: "{thesis_title.en}"),
+  abstract: (
+    cs: "
+      Sem vyplňte abstrakt své práce v češtině.
+    ",
+    en: "
+      Insert the abstract of your theses in English here.
+    "
+  ),
   author: "{author_info.name}",
   author_pronouns: "{author_info.pronouns}",
 <collaborators.has_supervisor:  supervisor: "{collaborators.supervisor_name}",