doc: Document breaking changes in BREAKING_CHANGES.md

BRAKING_CHANGES.md

@@ -0,0 +1,63 @@
+This file contains braking changes that have been made in this branch to
+make it easier to switch from [hoob3rt/lualine.nvim](https://github.com/hoob3rt/lualine.nvim)
+In this file contains changes in timed order . It's possible breaking change
+has been made to several times to same thing . In that case the one in the
+bottom indicates current state.
+
+### Color option unification
+color_added, color_modified, color_removed options in diff & color_error,
+color_warning, color_info, color_hint too only fg color that was different
+from other color options that took fg ,bg & gui changes were made to make
+them similar.
+
+So instead of
+```lua
+color_added = '#rrbbgg',
+```
+You'll have
+```lua
+color_added = { fg = '#rrbbgg' }
+```
+for same effect.
+
+### Theme rename
+So themes were renamed so they are same as their `g:color_name`
+- oceanicnext      -> OceanicNext
+- papercolor       -> PaperColor
+- tomorrow         -> Tomorrow
+- gruvbox_material -> gruvbox-material
+- modus_vivendi    -> modus-vivendi
+
+### function components now receive some default parameters
+Now function components receive same args as `update_status`. So fuctions
+signature is now
+```lua
+function(self, is_active)
+```
+`self` is a table that represents the component in lualine & `is_active` is
+a boolean value that indicates whether the function is being evaluated
+for active statusline or inactive statusline. This means function components
+can be more versatile. But also means you can't use functions that take
+optional arguments directly as function component . `lsp_status` is such
+a cases it takes an optional `winid` in first argument .
+You can wrap it with a function so those self & is_active doesn't
+get passed to `lsp_status`
+```lua
+lualine_c = { function() return require'lsp_status'.status() end}
+```
+
+### Options simplification
+See #24 for details
+- `upper` & `lower` removed use `string.upper/lower` in `fmt` option.
+- separators are specified by left & right instead of position
+  instead of `{'>', '<'}` you'll use `{left= '>', right='<'}`.
+- `left_padding` & `right_padding` removed. You can specify left or right
+  padding with padding option like padding = `{ left = 5 }`
+- Option rename:
+ - condition -> cond
+ - format -> fmt
+ - disable_text -> icon_only
+- color_added, color_modified, color_removed are now available as added,
+modified, removed in diff_color table option
+- color_error, color_warning, color_info, color_hint are now available
+as error, warning, info, hint in diagnostics_color table option

README.md

@@ -11,6 +11,14 @@ A fast and easy to configure statusline plugin for neovim
 
 `lualine.nvim` requires neovim 0.5
 
+<!-- panvimdoc-ignore-start -->
+
+This is a fork of [hoob3rt/lualine.nvim](https://github.com/hoob3rt/lualine.nvim).
+If you're switching from there please checkout [BREAKING_CHANGES.md](./BREAKING_CHANGES.md)
+to see what you may have to change in your config.
+
+<!-- panvimdoc-ignore-end -->
+
 ## Contributing
 
 Feel free to create an issue/pr if you want to see anything else implemented.