Show story description markdown preview by default

Change-Id: I1567c12f7fcd39f058de723691eb30271d377d47
Task: 30800
Story: 2005596

src/app/services/directive/markdown.js

@@ -41,7 +41,8 @@ angular.module('sb.services')
             link: function(scope, elem) {
                 scope.$watch('content', function(newVal) {
                     var html = md.render(newVal);
-                    elem.html('<div>' + $sanitize(html) + '</div>');
+                    elem.html('<div class="preview-story">' +
+                     $sanitize(html) + '</div>');
                 }, true);
             }
         };

src/app/stories/template/new.html

@@ -41,7 +41,7 @@
 
                         <div class="col-sm-10">
                             <textarea id="description"
-                                      class="form-control"
+                                      class="form-control new-textArea"
                                       ng-model="story.description"
                                       msd-elastic
                                       required

src/theme/base/_stories.scss

@@ -43,4 +43,41 @@
 
 #query .dropdown-menu > li{
     padding-left:1rem;
+}
+
+.preview-story {
+    /* scroll bar shown if needed*/
+    max-height: 200px;
+    overflow-y: auto;
+
+    pre{
+        background-color: #fff;
+        border: none;
+    }
+    
+    /* scroll bar styling*/
+    /* width */
+    &::-webkit-scrollbar {
+        width: 10px;
+    }
+  
+    /* Track */
+    &::-webkit-scrollbar-track {
+        box-shadow: inset 0 0 5px grey; 
+        border-radius: 10px;
+    }
+    
+    /* Handle */
+    &::-webkit-scrollbar-thumb {
+        background: grey; 
+        border-radius: 10px;
+    }
+    
+}
+
+.new-textArea{
+    /* scroll bar shown if needed*/
+    max-height: 200px;
+    overflow-y: auto;
+
 }