Update documentation to include meta docs

docs/guide/existing-game.md

@@ -1,6 +1,9 @@
-**TODO**
+**This page is under construction!**
 
 ## Summary
+* Tools to port existing games are in progress!
+    * [rbxlx-to-rojo](https://github.com/rojo/rbxlx-to-rojo)
+    * `rojo export` ([issue #208](https://github.com/rojo-rbx/rojo/issues/208))
 * Can port as much or as little of your game as you like
     * Rojo can manage just a slice of your game!
 * Some Roblox idioms aren't very well supported

docs/guide/installation.md

@@ -13,6 +13,9 @@ Rojo has two components:
 
     The plugin will show errors in the Roblox Studio output window if there is a version mismatch.
 
+## Visual Studio Code Extension
+If you use Visual Studio Code, you can install [the Rojo VS Code extension](https://marketplace.visualstudio.com/items?itemName=evaera.vscode-rojo), which will install both halves of Rojo for you. It even has a nifty UI to sync files and start/stop the Rojo server!
+
 ## Installing the CLI
 
 ### Installing from GitHub
@@ -40,7 +43,4 @@ Download the attached `rbxm` file and put it into your Roblox Studio plugins fol
 {: align="center" }
 
 ### Installing from Roblox.com
-Visit [Rojo's Roblox.com Plugin page](https://www.roblox.com/library/1997686364/Rojo-0-5-0-alpha-3) in Roblox Studio and press **Install**.
+Visit [Rojo's Roblox.com Plugin page](https://www.roblox.com/library/1997686364/Rojo-0-5-0-alpha-3) in Roblox Studio and press **Install**.
-
-## Visual Studio Code Extension
-If you use Visual Studio Code, you can install [Evaera's unofficial Rojo extension](https://marketplace.visualstudio.com/items?itemName=evaera.vscode-rojo), which will install both halves of Rojo for you. It even has a nifty UI to sync files and start/stop the Rojo server!

docs/guide/migrating-to-epiphany.md

@@ -55,4 +55,9 @@ All other values are considered children, where the key is the instance's name,
 ## Migrating Unknown Files
 If you used Rojo to sync in files as `StringValue` objects, you'll need to make sure those files end with the `txt` extension to preserve this in Rojo 0.5.x.
 
-Unknown files are now ignored in Rojo instead of being converted to `StringValue` objects.
+Unknown files are now ignored in Rojo instead of being converted to `StringValue` objects.
+
+## Migrating `init.model.json` files
+In Rojo 0.4.x, it's possible to create a file named `init.model.json` that lets you describe a model that becomes the container for all of the other files in the folder, just like `init.lua`.
+
+In Rojo 0.5.x, this feature has been replaced with `init.meta.json` files. See [Sync Details](../reference/sync-details) for more information about these new files.

docs/reference/sync-details.md

@@ -3,17 +3,18 @@ This page aims to describe how Rojo turns files on the filesystem into Roblox ob
 [TOC]
 
 ## Overview
-| File Name      | Instance Type       |
+| File Name      | Instance Type             |
-| -------------- | ------------------- |
+| -------------- | ------------------------- |
-| any directory  | `Folder`            |
+| any directory  | `Folder`                  |
-| `*.server.lua` | `Script`            |
+| `*.server.lua` | `Script`                  |
-| `*.client.lua` | `LocalScript`       |
+| `*.client.lua` | `LocalScript`             |
-| `*.lua`        | `ModuleScript`      |
+| `*.lua`        | `ModuleScript`            |
-| `*.csv`        | `LocalizationTable` |
+| `*.csv`        | `LocalizationTable`       |
-| `*.txt`        | `StringValue`       |
+| `*.txt`        | `StringValue`             |
-| `*.model.json` | Any                 |
+| `*.model.json` | Any                       |
-| `*.rbxm`       | Any                 |
+| `*.rbxm`       | Any                       |
-| `*.rbxmx`      | Any                 |
+| `*.rbxmx`      | Any                       |
+| `*.meta.json`  | Modifies another instance |
 
 ## Limitations
 Not all property types can be synced by Rojo in real-time due to limitations of the Roblox Studio plugin API. In these cases, you can usually generate a place file and open it when you start working on a project.
@@ -24,7 +25,9 @@ Some common cases you might hit are:
 * `MeshPart.MeshId`
 * `HttpService.HttpEnabled`
 
-For a list of all property types that Rojo can reason about, both when live-syncing and when building place files, look at [rbx_tree's type coverage chart](https://github.com/LPGhatguy/rbx-tree#property-type-coverage).
+For a list of all property types that Rojo can reason about, both when live-syncing and when building place files, look at [rbx-dom's type coverage chart](https://github.com/rojo-rbx/rbx-dom#property-type-coverage).
+
+This limitation may be solved by [issue #205](https://github.com/rojo-rbx/rojo/issues/205) in the future.
 
 ## Folders
 Any directory on the filesystem will turn into a `Folder` instance unless it contains an 'init' script, described below.
@@ -88,4 +91,54 @@ Rojo supports both binary (`.rbxm`) and XML (`.rbxmx`) models generated by Roblo
 
 Support for the `rbxmx` is very good, while support for `rbxm` is still very early, buggy, and lacking features.
 
-For a rundown of supported types, check out [rbx-dom's type coverage chart](https://github.com/LPGhatguy/rbx-dom#property-type-coverage).
+For a rundown of supported types, check out [rbx-dom's type coverage chart](https://github.com/rojo-rbx/rbx-dom#property-type-coverage).
+
+## Meta Files
+New in Rojo 0.5.0-alpha.12 are meta files, named `.meta.json`.
+
+Meta files allow attaching extra Rojo data to models defined in other formats, like Roblox's `rbxm` and `rbxmx` model formats, or even Lua scripts.
+
+This can be used to set Rojo-specific settings like `ignoreUnknownInstances`, or can be used to set properties like `Disabled` on a script.
+
+Meta files can contain:
+
+* `className`: Changes the `className` of a containing `Folder` into something else.
+    * Usable only in `init.meta.json` files
+* `properties`: A map of properties to set on the instance, just like projects
+    * Usable on anything except `.rbxmx`, `.rbxm`, and `.model.json` files, which already have properties
+* `ignoreUnknownInstances`: Works just like `$ignoreUnknownInstances` in project files
+
+### Meta Files to set Rojo metadata
+Sometimes it's useful to apply properties like `ignoreUnknownInstances` on instances that are defined on the filesystem instead of within the project itself.
+
+### Meta Files for Disabled Scripts
+Meta files can be used to set properties on `Script` instances, like `Disabled`.
+
+If your project had `foo.server.lua` and you wanted to make sure it would be disabled, you could create a `foo.meta.json` next to it with:
+
+```json
+{
+    "properties": {
+        "Disabled": true
+    }
+}
+```
+
+### Meta Files for Tools
+If you wanted to represent a tool containing a script and a model for its handle, create a directory with an `init.meta.json` file in it:
+
+```json
+{
+    "className": "Tool",
+    "properties": {
+        "Grip": [
+            0, 0, 0,
+            1, 0, 0,
+            0, 1, 0,
+            0, 0, 1,
+        ]
+    }
+}
+```
+
+Instead of a `Folder` instance, you'll end up with a `Tool` instance with the `Grip` property set!