Add contributing guide (#545)

Author: jgollenz

CONTRIBUTING.md

@@ -0,0 +1,44 @@
+# Contributing Guide
+
+Thanks for wanting to help out with nvim-orgmode, we appreciate the effort!
+
+## Reporting Bugs/Features
+
+> :mega: Please always make a quick search in our [issue-tracker](https://github.com/nvim-orgmode/orgmode/issues) before reporting anything. If the bug/feature has already been reported, continue the conversation on the existing issue.
+
+We distinguish between `core` (part of [orgmode](https://orgmode.org/)) and `non-core` features.
+The former will be prioritized. Bugs get the highest priority.
+
+If you're reporting a `core` feature, please be sure to provide a link that describes it. There are several places where features could be documented, have a look at these [resources](https://orgmode.org/worg/#resources). The more info you provide the better!
+
+## Documentation
+
+If you spot something missing in our [docs](DOCS.md), don't hesitate making a PR. The [wiki](https://github.com/nvim-orgmode/orgmode/wiki) can be edited freely.
+
+## Code
+
+You can take a look at our [feature completeness](https://github.com/nvim-orgmode/orgmode/wiki/Feature-Completeness) list and see if any of the missing features catch your interest.
+
+If you prefer working on an issue that has been reported, please leave a comment voicing your interest.
+
+Please document any new code you add with [emmylua annotations](https://emmylua.github.io/annotation.html). Feel free to add annotations/docs to any existing functions integral to your PR that are missing them.
+
+### Tests
+
+ To run tests, [plenary.nvim](https://github.com/nvim-lua/plenary.nvim) and [nvim-treesitter](https://github.com/nvim-treesitter/nvim-treesitter) must be present in the nvim-orgmode directory:
+```
+git clone https://github.com/nvim-treesitter/nvim-treesitter
+git clone https://github.com/nvim-lua/plenary.nvim
+make test
+```
+
+### Formatting
+
+Formatting is done via [StyLua](https://github.com/JohnnyMorganz/StyLua). To format everything run:
+```
+make format
+```
+
+### Parser
+
+Parsing is done via builtin treesitter parser and the [tree-sitter-org](https://github.com/milisims/tree-sitter-org) grammar.

README.md

@@ -10,7 +10,7 @@
 
   Orgmode clone written in Lua for Neovim 0.8+
 
-  [Setup](#setup) • [Docs](/DOCS.md) • [Showcase](#showcase) • [Treesitter](#treesitter-info) • [Troubleshoot](#troubleshoot) • [Plugins](#plugins) • [Development](#development) • [Kudos](#thanks-to)
+  [Setup](#setup) • [Docs](/DOCS.md) • [Showcase](#showcase) • [Treesitter](#treesitter-info) • [Troubleshoot](#troubleshoot) • [Plugins](#plugins) • [Contributing](CONTRIBUTING.md) • [Kudos](#thanks-to)
 
 
 </div>
@@ -371,29 +371,21 @@ and a good foundation for external plugins.<br />
 If you want to build a plugin, post suggestions and improvements on [Plugins infrastructure](https://github.com/nvim-orgmode/orgmode/issues/26)
 issue.
 
-## Development
+### :wrench: API
 
-### Tests
- To run tests, [plenary.nvim](https://github.com/nvim-lua/plenary.nvim) and [nvim-treesitter](https://github.com/nvim-treesitter/nvim-treesitter) must be present in the nvim-orgmode directory:
-```
-git clone https://github.com/nvim-treesitter/nvim-treesitter
-git clone https://github.com/nvim-lua/plenary.nvim
-make test
-```
+Documentation for our work-in-progress API can be found [here](doc/orgmode_api.txt)
 
-### Documentation
-Hosted documentation is on: [https://nvim-orgmode.github.io/](https://nvim-orgmode.github.io/)
+## Contributing
 
-Vim documentation is auto generated from [DOCS.md](DOCS.md) file with [md2vim](https://github.com/FooSoft/md2vim).
+See [CONTRIBUTING.md](CONTRIBUTING.md)
 
-### Formatting
-Formatting is done via [StyLua](https://github.com/JohnnyMorganz/StyLua). To format everything run:
-```
-make format
-```
+## Documentation
+
+If you are just starting out with orgmode, have a look at the [Getting Started](https://github.com/nvim-orgmode/orgmode/wiki/Getting-Started) section in our wiki.
 
-### Parser
-Parsing is done via builtin treesitter parser and [tree-sitter-org](https://github.com/milisims/tree-sitter-org) grammar.
+Vim documentation is auto generated from [DOCS.md](DOCS.md) file with [md2vim](https://github.com/FooSoft/md2vim).
+
+Hosted documentation is on: [https://nvim-orgmode.github.io/](https://nvim-orgmode.github.io/)
 
 ## Roadmap
 * [X] Support searching by properties