Fix delete responses

Add relationship from visualization to project.
Add plot-type attribute.

models/plot.js

@@ -9,7 +9,8 @@ var plotSchema = new Schema({
   signal: { type: String, required: true },
   width: { type: Number, required: true },
   height: { type: Number, required: true },
-  title: { type: String }
+  title: { type: String },
+  type: { type: String, required: true }
 });
 
 module.exports = mongoose.model('Plot', plotSchema);

models/visualization.js

@@ -6,6 +6,7 @@ var Schema = mongoose.Schema;
 // visualization model
 var visualizationSchema = new Schema({
   name: { type: String, required: true },
+  project: { type: Schema.Types.ObjectId, ref: 'Project', required: true },
   plots: [{ type: Schema.Types.ObjectId, ref: 'Plot' }]
 });
 

routes/plots.js

@@ -74,7 +74,7 @@ router.route('/plots/:id').delete(function(req, res) {
       return res.send(err);
     }
 
-    res.send({ plot: plot });
+    res.send({});
   });
 });
 

routes/projects.js

@@ -90,7 +90,7 @@ router.route('/projects/:id').delete(function(req, res) {
       return res.send(err);
     }
 
-    res.send({ project: project });
+    res.send({});
   });
 });
 

routes/users.js

@@ -89,7 +89,7 @@ router.route('/users/:id').delete(auth.validateAdminLevel(1), function(req, res)
       return res.send(err);
     }
 
-    res.send({ user: user });
+    res.send({});
   });
 });
 

routes/visualizations.js

@@ -74,7 +74,7 @@ router.route('/visualizations/:id').delete(function(req, res) {
       return res.send(err);
     }
 
-    res.send({ visualization: visualization });
+    res.send({});
   });
 });