add contribution section

README.md

@@ -1,6 +1,61 @@
 ## NvChad theme plugin
+
+- This plugin's a whole re-write of Norcalli's plugin.
  
 (Note: This theme plugin is supposed to be used along with [NvChad](https://github.com/NvChad/NvChad) only so watchout!)
 
 Base45 theming plugin 
- 
+
+## Contribute for new themes 
+
+- go to hl_themes and add your file, ex: atheme.lua
+```lua
+-- atheme.lua file be like 
+
+local M = {}
+
+M.base_30 = {
+  -- some colors 
+}
+
+M.base_16 = {
+  -- some colors 
+}
+
+M = require("base16").override_theme(M, "atheme")
+
+return M
+```
+
+## Understanding theme variables 
+
+- Use a color lightening/darkening tool, such as this https://siduck.github.io/hex-tools/
+
+```
+black = usually your theme bg (this should be the same as base00 in doom-base16.lua)
+darker_black = 6% darker than black
+black2 = 6% lighter than black
+
+onebg = 10% lighter than black
+oneb2 = 19% lighter than black
+oneb3 = 27% lighter than black
+
+grey = 40% lighter than black (the % here depends so choose the perfect grey!)
+grey_fg = 10% lighter than grey
+grey_fg2 = 20% lighter than grey
+light_grey = 28% lighter than grey
+
+baby_pink = 15% lighter than red or any babypink color you like!
+line = 15% lighter than black 
+
+nord_blue = 13% darker than blue 
+sun = 8% lighter than yellow
+
+statusline_bg = 4% lighter than black
+lightbg = 13% lighter than statusline_bg
+lightbg2 = 7% lighter than statusline_bg
+
+folder_bg = blue color
+
+(note : the above values are mostly approx values so its not compulsory that you have to use those exact numbers , test your theme i.e show it in the PR to get feedback from @siduck)
+```