docs: create the building-a-blog stub article

docs/docs/building-a-blog.md

@@ -2,7 +2,63 @@
 title: Building a blog
 ---
 
-This is a stub. Help our community expand it.
 
-Please use the [Gatsby Style Guide](/docs/gatsby-style-guide/) to ensure your
-pull request gets accepted.
+### Building a blog
+
+Using gatsby-starter-blog you will build a full-featured blog. 
+
+### Prerequisites
+
+You must know how to set up a basic Gatsby project based on a starter. If you need to, check the [main tutorial](https://www.gatsbyjs.org/tutorial).
+
+### Setting up blog metadata
+
+Edit the siteMetadata to set the site title, author, and other properties: 
+
+```js:title=gatsby-config.js
+siteMetadata: {
+    title: `Gatsby Starter Blog`,
+    author: `Kyle Mathews`,
+    description: `A starter blog demonstrating what Gatsby can do.`,
+    siteUrl: `https://gatsby-starter-blog-demo.netlify.com/`,
+    social: {
+      twitter: `kylemathews`,
+    },
+ },
+```
+
+### Adding articles
+
+To create an article, add a new folder to `/content/blog/`. The name of this folder is the route on which the article is available. You write the article itself in the `index.md` file under the created folder. 
+
+#### Article metadata
+
+All the article metadata such as the `title` come from the header of the index.md file. You can access this data under the `frontmatter` object. 
+
+content/blog/hello-world/index.md
+---
+title: Hello World
+date: '2015-05-01T22:12:03.284Z'
+ ---
+
+#### Adding more data to frontmatter
+
+You can include more data in `frontmatter` like `readTime` for example. To use this data, you also have to change the page queries that are reading this data:
+
+```js:title=src/templates/blog-post.js
+frontmatter {
+ title
+ date(formatString: "MMMM DD, YYYY")
+ readTime
+}
+`
+```
+
+```js:title=src/pages/index.js
+frontmatter {
+ date(formatString: "MMMM DD, YYYY")
+ title
+ readTime
+}
+`
+```