SCSS variables overridable

Added !default

Author: Bruno Mendola

scss/_variables.scss

@@ -1,9 +1,9 @@
-$brand-gradient-left: #318be3;
-$brand-gradient-right: #04befe;
-$navbar-height: 3.5rem;
-$user-info-height : 222px;
-$sidebar-width-lg: 215px;
-$sidebar-width-icon: 70px;
+$brand-gradient-left: #318be3 !default;
+$brand-gradient-right: #04befe !default;
+$navbar-height: 3.5rem !default;
+$user-info-height : 222px !default;
+$sidebar-width-lg: 215px !default;
+$sidebar-width-icon: 70px !default;