do not save username since we are already saving user_id

plugin.rb

@@ -567,7 +567,7 @@ SQL
 
   # Reimplement a couple ActiveRecord methods, but use PluginStore for storage instead
   class DataExplorer::Query
-    attr_accessor :id, :name, :description, :sql, :created_by, :created_at, :username
+    attr_accessor :id, :name, :description, :sql, :created_by, :created_at
 
     def initialize
       @name = 'Unnamed Query'
@@ -609,7 +609,7 @@ SQL
 
     def self.from_hash(h)
       query = DataExplorer::Query.new
-      [:name, :description, :sql, :created_by, :created_at, :username].each do |sym|
+      [:name, :description, :sql, :created_by, :created_at].each do |sym|
         query.send("#{sym}=", h[sym].strip) if h[sym]
       end
       query.id = h[:id].to_i if h[:id]
@@ -623,8 +623,7 @@ SQL
         description: @description,
         sql: @sql,
         created_by: @created_by,
-        created_at: @created_at,
-        username: @username
+        created_at: @created_at
       }
     end
 
@@ -943,7 +942,6 @@ SQL
       query = DataExplorer::Query.from_hash params.require(:query)
       query.created_at = Time.now.strftime("%b %e, %Y")
       query.created_by = current_user.id.to_s
-      query.username = User.find(query.created_by).username
       query.id = nil # json import will assign an id, which is wrong
       query.save
 
@@ -1084,6 +1082,10 @@ SQL
     def param_info
       object.params.map(&:to_hash) rescue nil
     end
+
+    def username
+      User.find(created_by).username rescue nil
+    end
   end
 
   DataExplorer::Engine.routes.draw do