New page "Basics of BuildPacks" under the Getting Started side menu

- Changed `app-journey` weight to 3 to move it down

- Added a new "Basics of Buildpacks" page

- Added a new image to depict what constitutes a `lifecycle`

Signed-off-by: QuillPusher <[email protected]>

Author: QuillPusher

content/docs/app-journey.md

@@ -1,6 +1,6 @@
 +++
 title="An App's Brief Journey from Source to Image"
-weight=2
+weight=3
 getting-started=true
 +++
 

content/docs/buildpack-basics.md

@@ -0,0 +1,63 @@
++++
+title="Basics of BuildPacks"
+weight=2
+getting-started=true
++++
+
+## Basic Concepts
+
+### What is a Buildpack?
+
+A `buildpack` is software that transforms application source code into
+executable files by analyzing the code and determining the best way to
+build it.
+
+![buildpacks](/images/what.svg)
+
+### What is a Builder?
+
+A builder is an image that contains all the components necessary to
+execute a build (for example, an ordered combination of buildpacks, a build
+image and other files and configurations).
+
+![create-builder diagram](/images/create-builder.svg)
+
+### What is a Lifecycle?
+
+A lifecycle is a series of steps that are used to create and manage a
+buildpack. `create` is used to analyze, detect, restore, build, and export
+buildpack execution. Next, `launcher` can be used to launch the application.
+Finally, `rebase` can be used to push the latest changes to an existing
+buildpack. All of these steps are part of a lifecycle.
+
+![lifecycle](/images/lifecycle.png)
+
+### What is a Platform
+
+A platform typically refers to an organization or service provider (e.g.,
+kpack, Tekton, Fly.io, Digital Ocean, Google Cloud, Heroku, SalesForce, etc.)
+that incorporates Buildpacks within their products to make buildpack
+functionality available to their end-users (typically, application
+developers). 
+
+A platform can be a:
+
+- A local CLI tool
+- A plugin for a continuous integration service
+- A cloud application platform
+
+## Who uses Buildpacks (Personas)
+
+### App Developers
+
+Regular Application developers that utilize Buildpacks in their app packaging
+workflows.
+
+### Platform Operators
+
+Operators of platforms (Google Cloud, Salesforce, etc.) that incorporate
+Buildpacks within their platforms to simplify the end-user experience.
+
+### Buildpack Authors
+
+Buildpacks' internal developers working on Buildpack features.