switched everything over to Mongoose

backend/models/system_stat.js

@@ -0,0 +1,27 @@
+var mongoose = require('mongoose');
+
+let decodeErrorSchema = mongoose.Schema({
+  errorHistory: [Number],
+  spikeHistory: [Number],
+})
+
+let talkgroupStatsSchema = mongoose.Schema({
+  callCountHistory: [Number],
+  callAvgLenHistory: [Number]
+})
+var systemStatSchema = mongoose.Schema({
+  callTotals: [Number],
+  uploadErrors: [Number],
+  decodeErrorsFreq: {
+    type: Map,
+    of: decodeErrorSchema
+  },
+  talkgroupStats: {
+    type: Map,
+    of: talkgroupStatsSchema
+  },
+  shortName: String
+}, { collection: 'system_stats' });
+
+
+module.exports = mongoose.model('SystemStat', systemStatSchema);