initial pass on adding projectionist info to readme

Author: zolrath

README.md

@@ -225,3 +225,44 @@ You can run any `mix` command in your project, complete with... autocomplete!
 - Phoenix Controllers
 - Phoenix Channels
 - Wallaby/Hound Feature tests
+
+Using Projectionist you can easily generate and swap between source files and test files.
+
+#### Alternate File
+The most basic usage is to easily swap between a source file and it's associated test.
+
+While editing a **source file** such as `lib/blog_web/live/post_live.ex`, by executing the `:A` command a new buffer will be opened with the **test file** `test/blog_web/live/post_live_test.exs`.
+
+#### Other Alternates
+While the `:A` command can easily switch between an `.ex` file and its test.
+There are other instances of associated files, such as [Colocated Phoenix Templates](https://hexdocs.pm/phoenix_live_view/Phoenix.LiveView.html#module-colocating-templates).
+In these situations you may have a source file as well as a template file.
+
+While editing a **source file** such as `lib/blog_web/live/post_live.ex`, by executing the `:Eheex` command a new buffer will be opened with the **heex file** lib/blog_web/live/post_live.html.heex`.
+
+If the `heex` file does not exist you will be prompted to create it, if desired.
+
+Similarly, to swap back to the LiveView execute the `:Eliveview` command.
+
+#### Create files
+In the case where a source file does not exist one can be created by supplying a directory and name to the `E` commands.
+
+`:Eliveview blog_web/post_live` creates a LiveView at `lib/blog_web/live/post_live.ex` with a basic LiveView starter template defining the module.
+`:Econtroller blog_web/post` creates a Controller at `lib/blog_web/controllers/post.ex` with a basic Controller starter template defining the module.
+
+#### Projections
+The ':E<filetype>' command can be run with any of the following projections in order to create/switch between files.
+
+- source *(lib/\*.ex)*
+- controller *(lib/\*\*/controllers/\*_controller.ex)*
+- view *(lib/\*\*/views/\*_view.ex)*
+- html *(lib/\*\*/controllers/\*_html.ex)*
+- json *(lib/\*\*/controllers/\*_json.ex)*
+- component *(lib/\*\*/components/\*.ex)*
+- liveview *(lib/\*\*/live/\*.ex)*
+- livecomponent *(lib/\*\*/live/\*_component.ex)*
+- heex *(lib/\*\*/live/\*.html.heex)*
+- leex *(lib/\*\*/live/\*.html.leex)*
+- channel *(lib/\*\*/channels/\*_channel.ex)*
+- test *(test/\*\*/<projectiontype>/\*_test.exs)*
+- feature *(test/\*\*/features/*_test.exs)*