added gruvbox theme

lua/custom/plugins/colorscheme.lua

@@ -0,0 +1,35 @@
+return {
+  {
+    'ellisonleao/gruvbox.nvim',
+    priority = 1000,
+    config = true,
+    opts = function()
+      -- Default options:
+      require('gruvbox').setup {
+        terminal_colors = true, -- add neovim terminal colors
+        undercurl = true,
+        underline = true,
+        bold = true,
+        italic = {
+          strings = true,
+          emphasis = true,
+          comments = true,
+          operators = false,
+          folds = true,
+        },
+        strikethrough = true,
+        invert_selection = false,
+        invert_signs = false,
+        invert_tabline = false,
+        invert_intend_guides = false,
+        inverse = true, -- invert background for search, diffs, statuslines and errors
+        contrast = '', -- can be "hard", "soft" or empty string
+        palette_overrides = {},
+        overrides = {},
+        dim_inactive = false,
+        transparent_mode = false,
+      }
+      vim.cmd.colorscheme 'gruvbox'
+    end,
+  },
+}