add server to monorepo.

packages/server/src/lib/Cachable/CachableModel.js

@@ -0,0 +1,16 @@
+import BaseModel from 'models/Model';
+import CacheService from '@/services/Cache';
+
+export default (Model) => {
+  return class CachableModel extends Model{
+    static flushCache(key) {
+      const modelName = this.name;
+
+      if (key) {
+        CacheService.del(`${modelName}.${key}`);
+      } else {
+        CacheService.delStartWith(modelName);
+      }
+    }
+  };
+} 

packages/server/src/lib/Cachable/CachableQueryBuilder.js

@@ -0,0 +1,69 @@
+import { QueryBuilder } from 'objection';
+import crypto from 'crypto';
+import CacheService from '@/services/Cache';
+
+export default class CachableQueryBuilder extends QueryBuilder{
+
+  async then(...args) {
+    // Flush model cache after insert, delete or update transaction.
+    if (this.isInsert() || this.isDelete() || this.isUpdate()) {
+      this.modelClass().flushCache();
+    }
+    if (this.cacheTag && this.isFind()) {
+      this.setCacheKey();
+      return this.getOrStoreCache().then(...args);
+    } else {
+      const promise = this.execute();
+    
+      return promise.then((result) => {
+        this.setCache(result);
+        return result;
+      }).then(...args);
+    }
+  }
+
+  getOrStoreCache() {
+    const storeFunction = () => this.execute();
+
+    return new Promise((resolve, reject) => {
+      CacheService.get(this.cacheKey, storeFunction)
+        .then((result) => { resolve(result); });
+    });
+  }
+
+  setCache(results) {
+    CacheService.set(`${this.cacheKey}`, results, this.cacheSeconds);
+  }
+
+  generateCacheKey() {
+    const knexSql = this.toKnexQuery().toSQL();
+    const hashedQuery = crypto.createHash('md5').update(knexSql.sql).digest("hex");
+
+    return hashedQuery;
+  }
+
+  remember(key, seconds) {
+    const modelName = this.modelClass().name;
+
+    this.cacheSeconds = seconds;
+    this.cacheTag = (key) ? `${modelName}.${key}` : modelName;
+
+    return this;
+  }
+
+  withGraphFetched(relation, settings) {
+    if (!this.graphAppends) {
+      this.graphAppends = [relation];
+    } else {
+      this.graphAppends.push(relation);
+    }
+    return super.withGraphFetched(relation, settings);
+  }
+
+  setCacheKey() {
+    const hashedQuery = this.generateCacheKey();
+    const appends = (this.graphAppends || []).join(this.graphAppends, ',');
+
+    this.cacheKey = `${this.cacheTag}.${hashedQuery}.${appends}`;
+  }
+}