Revert "set layout margin-bottom 50px"

Because .content class used in several other places and this change add
unnecessary margint ot it

This reverts commit f8807281.

app/assets/stylesheets/main/layout.scss

@@ -16,5 +16,5 @@ body {
 }
 
 .container .content {
-  margin: 0 0 50px;
+  margin: 0 0;
 }