Start the Creating a Package doc

docs/packages/authoring-packages.md

@@ -200,3 +200,12 @@ your grammar supports:
   'ron'
 ]
 ```
+
+## Writing Tests
+
+Your package **should** have tests, and if they're placed in the _spec_ directory,
+they can be run by Atom.
+
+Under the hood, [Jasmine](https://github.com/pivotal/jasmine) is being used to run
+to execute the tests, so you can assume that any DSL available there is available
+to your package as well.

docs/packages/creating_a_package.md

@@ -0,0 +1,60 @@
+# Creating Packages
+
+Let's take a look at creating our first package.
+
+Atom has a command you can enter that'll create a package for you:
+`package-generator:generate`. Otherwise, you can hit `meta-p`, and start typing
+"Package Generator." Once you activate this package, it'll ask you for a name for
+your new package. Let's call ours _changer_.
+
+Now, _changer_ is going to have a default set of folders and files created for us.
+Hit `meta-R` to reload Atom, then hit `meta-p` and start typing "Changer." You'll
+see a new `Changer:Toggle` command which, if selected, pops up a new message. So
+far, so good!
+
+In order to demonstrate the capabilities of Atom and its API, our Changer plugin
+is going to do two things:
+
+1. It'll show only modified files in the file tree
+2. It'll append a new pane to the editor with some information about the modified
+files
+
+Let's get started!
+
+## Changing Keybindings and Commands
+
+Since Changer is primarily concerned with the file tree, let's write a keybinding
+that works only when the tree is active. Instead of using the default `toggle`,
+our keybinding executes a new command called `magic`.
+
+_keymaps/changer.cson_ can easily become this:
+
+```cson
+'.tree-view-scroller':
+  'ctrl-V': 'changer:magic'
+```
+
+`.tree-view-scroller` represents the parent container for the tree view. Also,
+notice that the keybinding is called `ctrl-V`--that's actually `ctrl-shift-v`.
+You can use capital letters to denote using `shift` for your binding.
+
+To bind keybindings to a command, we'll use the `rootView.command` method. This
+takes a command name and executes a function in the code. For example:
+
+```coffeescript
+rootView.command "changer:magic", => @magic()
+```
+
+It's common practice to namespace your commands with your package name, and separate
+it with a colon (`:`). Rename the existing `toggle` method to `magic` to get the
+binding to work.
+
+Reload the editor, click on the tree, hit your keybinding, and...nothing happens! What the heck?!
+
+Open up the _package.json_ file, and notice the key that says `activationEvents`.
+Basically, this tells Atom to not load a package until it hears a certain event.
+Let's change the event to `changer:magic` and reload the editor.
+
+Hitting the key binding on the tree now works!
+
+## Working with styles