added /materials route

src/models/material.ts

@@ -0,0 +1,16 @@
+import mongoose from 'mongoose';
+
+const MaterialSchema = new mongoose.Schema({
+  name: {type: String, index: {unique: true}},
+  supplier: String,
+  group: String,
+  mineral: String,
+  glass_fiber: String,
+  carbon_fiber: String,
+  numbers: [{
+    color: String,
+    number: Number
+  }]
+});
+
+export default mongoose.model('material', MaterialSchema);