Add instructions for and ignore files related to using bundle

.gitignore

@@ -1,2 +1,4 @@
 /vendor
 _site/
+/.bundle
+/vendor

README.md

@@ -1,2 +1,10 @@
-gergelypolonkai.github.io
-=========================
+# gergely.polonkai.eu
+
+## Initial start
+
+```
+git clone $REPO
+cd $REPO
+bundle install --path vendor/bundle
+bundle exec jekyll server
+```

_config.yml

@@ -7,7 +7,7 @@ timezone: Europe/Budapest
 name: Gergely Polonkai
 paginate: 10
 paginate_path: "/blog/page/:num"
-exclude: ['README.md', 'Gemfile', 'Gemfile.lock', 'CNAME', ".hyde.el"]
+exclude: ['README.md', 'Gemfile', 'Gemfile.lock', 'CNAME', ".hyde.el", "vendor"]
 include: ['.well-known']
 plugins:
   - jekyll-gist