docs(help): add introduction

Author: rez1-dev

README.md

@@ -631,7 +631,7 @@ hi CompetiTestWrong   ctermfg=red    guifg=#ff0000
 	- [x] Customizable folder structure for downloaded problems and contests
 - [x] Templates for files created when receiving problems or contests
 - [ ] Integration with tools to submit solutions ([api-client](https://github.com/online-judge-tools/api-client) or [cpbooster](https://github.com/searleser97/cpbooster))
-- [ ] Write Vim docs
+- [x] Write Vim docs
 - [x] Customizable highlights
 - [x] Resizable UI
 

doc/competitest.nvim

@@ -0,0 +1,25 @@
+================================================================================
+INTRODUCTION                                               *competitest.nvim*
+
+CompetiTest.nvim is a testcase manager and checker. It saves you time
+in competitive programming contests by automating common tasks related
+to testcase management.
+
+Features:
+- Manage testcases:
+    - add / edit / delete testcases
+- Compile and run solutions
+- Compare program output with expected answers
+
+Additional:
+- Interactive UI to inspect results and outputs
+- Competitive Companion integration:
+    - download problems, contests and testcases
+- Flexible configuration:
+    - customizable compile and run commands
+    - customizable UI layout
+    - customizable testcase storage
+
+More information: https://github.com/xeluxee/competitest.nvim
+
+ vim:tw=78:ts=8:ft=help:norl:

doc/tags

@@ -0,0 +1 @@
+competitest.nvim    competitest.txt    /*competitest.nvim*