git: Update repository HEAD in create_branch().

src/git.cpp

@@ -113,6 +113,7 @@ void create_branch()
 {
     const auto id{get_last_id() + 1};
     const string branch_name = "web-" + std::to_string(id);
+    const string ref_name{"refs/heads/" + branch_name};
     git_oid oid_parent;
     git_commit *commit;
 
@@ -125,6 +126,8 @@ void create_branch()
     git_reference *branch;
     // Create new branch.
     check(git_branch_create(&branch, _repo, branch_name.c_str(), commit, 0));
+
+    check(git_repository_set_head(_repo, ref_name.c_str()));
 }
 
 void commit(const entry_type &entry)