docs(guide): start codebase overview

- add github link in sidebar

guide/SUMMARY.md

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 * [Components](ref://components/index.html)
 * TODO Sketch file?
+* [TDS on GitHub](https://github.com/TelusDigital/tds)
 
 ## Guide
 

guide/codebase-overview.md

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 # Codebase overview
 
+A description of the structure of the codebase, conventions being followed, and principles.
 
-Coming soon...
+## Tools
 
-A description of the structure of the codebase, conventions being followed, and principles.
+The TDS codebase maintains a set of organisational and syntactical standards.
+We utilise the following tools for the development, release, and distribution processes:
+
+- [Styleguidist](https://react-styleguidist.js.org/): component props are parsed and converted
+to documentation.
+- [Rollup](https://rollupjs.org/): Rollup delivers a component package with tree-shaken 
+methods, scoped CSS, 
+- [ES2015+](https://github.com/lukehoban/es6features): throughout this codebase, we utilise 
+JavaScript patterns such as ternary operators,
+deconstructors, and spread operators
+- [CSS Modules](https://github.com/css-modules/css-modules): facilitates the buildup of scoped 
+CSS while maintaining the familiar interface of SCSS
+- [Yarn](https://github.com/css-modules/css-modules): we chose Yarn as our node package 
+manager for its speed and deep dependency version locking. It is used in our build pipelines
+for deployment to npmjs.com
+
+## Component structure & standards
+
+All TDS components have a common directory structure and set of standards. Where you have a
+component named `PriceLock`, the files are organized like this:
+
+```
+/src/components/
+│
+└─── PriceLock
+    │  PriceLock.md
+    │  PriceLock.jsx
+    │  PriceLock.modules.scss
+    │
+    └─── __tests__
+        │  PriceLock.spec.jsx
+        |
+        └─── __snapshots__
+            |  PriceLock.spec.jsx.snap
+```
+
+Here you may notice our standards:
+
+- Use PascalCase for all file names
+- Avoid non-verbose filenames such as `index.jsx`
+- Every component must include a set of unit tests and snapshot
+- If a component requires custom styling, use CSS Modules and suffix your scss file with `.modules.scss`
+- To include custom documentation, use `<ComponentName>.md`
+
+## Building components
+
+### Creating new components from scratch
+
+When starting fresh, you can use the scaffolding script to generate a component directory structure:
+
+```sh
+yarn scaffold PriceLock
+
+# This will output a set of files in the aforementioned structure
+```
+
+### JSX Patterns
+
+Coming soon...