docs(schema): add information about how to use dbt

Author: hassankhan

docs/content/Schema/Advanced/Using-dbt.mdx

@@ -0,0 +1,81 @@
+---
+title: Using dbt
+permalink: /schema/advanced/using-dbt
+category: Data Schema
+subCategory: Advanced
+menuOrder: 10
+---
+
+<InfoBox>
+
+This functionality only works with models written in JavaScript, not YAML.
+
+</InfoBox>
+
+Cube's metrics layer is able to read metrics definitions from [dbt][dbt] via the
+[Metadata API][dbt-docs-metadata-api] and translate them into an equivalent Cube
+data model.
+
+## Connect dbt Core to Cube
+
+This can be done through reading the `dbt-project.yml` file.
+
+```javascript
+import dbt from '@cubejs-backend/dbt-schema-extension';
+
+asyncModule(async () => {
+  // `/dbt` is the path to a folder containing `dbt-project.yml`
+  await dbt.loadMetricCubesFromDbtProject('/dbt');
+});
+```
+
+## Connect dbt Cloud to Cube
+
+Create a `config.js` file as a sibling to the `schema/` folder in your Cube
+project:
+
+```javascript
+exports.dbtJobId = 65806;
+exports.dbtApiKey = 'YOUR_KEY_HERE';
+```
+
+Create a file called `dbt.js` in the `schema/` folder and enter the following
+code snippet:
+
+```javascript
+import dbt from '@cubejs-backend/dbt-schema-extension';
+import { dbtJobId, dbtApiKey } from '../config';
+
+asyncModule(async () => {
+  await dbt.loadMetricCubesFromDbtCloud(dbtJobId, dbtApiKey);
+});
+```
+
+You can then define cubes under the above snippet:
+
+```javascript
+import dbt from '@cubejs-backend/dbt-schema-extension';
+import { dbtJobId, dbtApiKey } from '../config';
+
+asyncModule(async () => {
+  await dbt.loadMetricCubesFromDbtCloud(dbtJobId, dbtApiKey);
+});
+
+cube('GithubCommitStatsCommitsCached', {
+  extends: GithubCommitStatsCommits,
+
+  preAggregations: {
+    main: {
+      measures: [commitsCount],
+      dimensions: [authorDomain, authorName],
+      timeDimension: timestamp,
+      granularity: 'day',
+      partitionGranularity: 'year',
+    },
+  },
+});
+```
+
+[dbt]: https://www.getdbt.com/
+[dbt-docs-metadata-api]:
+  https://docs.getdbt.com/docs/dbt-cloud-apis/metadata-api