README.md: typo

README.md

@@ -1,4 +1,4 @@
-To build Gluon, after checkeing out the repository change to the source root directory
+To build Gluon, after checking out the repository change to the source root directory
 to  perform the following commands:
 
     git clone git://github.com/freifunk-gluon/site-ffhl.git site # Get the Freifunk Lübeck site repository - or use your own!