chore: fixed refactor errors

app/controllers/invitations_controller.rb

@@ -86,7 +86,7 @@ def create_utility
 
   def check_user_before_invitation
     # user is the student you are inviting to your team
-    @user = User.find_by(username: params[:user][:name].strip)
+    @user = User.find_by(username: params[:user][:username].strip)
     # User/Author has information about the participant
     @student = AssignmentParticipant.find(params[:student_id])
     @assignment = Assignment.find(@student.parent_id)

app/models/team.rb

@@ -78,6 +78,7 @@ def full?
 
   # Add member to the team, changed to hash by E1776
   def add_member(user, _assignment_id = nil)
+
     raise "The user #{user.username} is already a member of the team #{name}" if user?(user)
 
     can_add_member = false
@@ -87,7 +88,7 @@ def add_member(user, _assignment_id = nil)
       parent = TeamNode.find_by(node_object_id: id)
       TeamUserNode.create(parent_id: parent.id, node_object_id: t_user.id)
       add_participant(parent_id, user)
-      ExpertizaLogger.info LoggerMessage.new('Model:Team', user.username, "Added member to the team #{id}")
+      ExpertizaLogger.info LoggerMessage.new('Model:Team', user.name, "Added member to the team #{id}")
     end
     can_add_member
   end