Update README.md
Merge pull request #2 from DerMambo/patch-1

Update README.md
Use 'declined' for declined change requests.
Merge pull request #3 from Rahbaran/master

Use 'declined' for declined change requests.
added intro course in top navbar
added footer (with contact details, imprint and terms)
updated logo
Merge pull request #4 from Rahbaran/master

added intro course in top navbar
minor bug fix + some wording
'Exercise' is now 'lesson'. Added 'other' category
make change request changes bold
make change request changes colourful ;)
Added Feedback/Support Forum