permissions.js

// Server

Votes.allow({
	insert: function (userId, vote){
		var voteCheck = Votes.findOne({user_id: userId, video_id: vote.video_id});
		if ( voteCheck ) {
			return false;
		} else {
			if ( userId && vote.user_id === userId ) {
				return true;
			} else {
				return false;
			}
		}
	},
	remove: function(userId, vote){
		if ( userId && vote.user_id === userId ) {
			return true;
		} else {
			return false;
		}
	}
});

room_page.js

// Template file

Template.roomPage.events({
  'click .proposed-videos-list li': function(){
		if ( !Meteor.userId() ) {
			$('#loginModal').modal('show');
			return;
		}
		
		var voteCheck = Votes.findOne({user_id: Meteor.userId(), video_id: this._id});

		if ( voteCheck ) {
			Votes.remove({_id: voteCheck._id});
		} else {
			Votes.insert({user_id: Meteor.userId(), video_id: this._id});
		}
	}
});