Fix meson and ninja commands and link bootstrap

.gitignore

@@ -1,6 +1,7 @@
 *~
 /.direnv/
 .test_info.*
+/src/root/static/bootstrap
 /src/sql/hydra-postgresql.sql
 /src/sql/hydra-sqlite.sql
 /src/sql/tmp.sqlite

README.md

@@ -80,8 +80,9 @@ $ nix build
 You can use the provided shell.nix to get a working development environment:
 ```
 $ nix develop
-$ mesonConfigurePhase
-$ ninja
+$ ln -svf ../../../build/src/bootstrap src/root/static/bootstrap
+$ meson setup build
+$ ninja -C build
 ```
 
 The development environment can also automatically be established using [nix-direnv](https://github.com/nix-community/nix-direnv).