Add urls to about us section

Author: daiyi

_config.yml

@@ -36,22 +36,22 @@ team:
     url: http://daveliepmann.com
   - name: Johanna
     image: johanna.jpg
-    url:
+    url: https://twitter.com/JohanannC
   - name: Julia
     image: julia.jpg
-    url:
+    url: https://twitter.com/anderspree
   - name: Lisa
     image: lislis.png
     url: http://lislis.de
   - name: Nils
     image: nils.png
-    url:
+    url: http://nils-blum-oeste.net
   - name: Saskia
     image: saskia.jpg
-    url:
+    url: http://saskialindner.com
   - name: Tibor
     image: tibor.jpg
-    url:
+    url: http://codebeige.net
   - name: Anna
     image: anna.jpg
     url: