diff --git a/.vimrc b/.vimrc
index f039431..2208227 100644
--- a/.vimrc
+++ b/.vimrc
@@ -4,11 +4,12 @@ filetype off                " required
 " set the runtime path to include Vundle and initialise
 set rtp+=~/.vim/bundle/Vundle.vim/
 call vundle#begin()
-
 " let Vundle manage Vundle, required
 Plugin 'VundleVim/Vundle.vim'
 " tree file explore
 Plugin 'preservim/nerdtree'
+" git status flags on NERDTree
+Plugin 'Xuyuanp/nerdtree-git-plugin'
 " code comment
 Plugin 'preservim/nerdcommenter'
 " auto complete
@@ -19,10 +20,10 @@ Plugin 'tmhedberg/SimpylFold'
 Plugin 'itchyny/lightline.vim'
 " git integration
 Plugin 'tpope/vim-fugitive'
+" indicates which lines have been modified in editor window
+Plugin 'airblade/vim-gitgutter'
 " syntax check
 Plugin 'dense-analysis/ale'
-" auto generates surround pairs
-Plugin 'jiangmiao/auto-pairs'
 
 " All of the plugins must be added before the following line
 call vundle#end()           " required
@@ -41,17 +42,29 @@ syntax on               " enable syntax highlighting
 colorscheme desert      " set `desert` as default colour scheme
 set autoindent          " indent when moving to the next while writing code
 set colorcolumn=80      " show 80 line indicator
+set cursorline          " show cursorline by default
 set encoding=utf-8      " show output in UTF-8 as YouCompleteMe requires
 set expandtab           " expand tabs into spaces
 set fileencoding=utf-8  " save file with UTF-8 encoding
 set fileformat=unix     " save file with LF line endings
+set hlsearch            " highlight the search results
 set laststatus=2        " show the statusline/tabline
 set number              " show line numbers
 set shiftwidth=4        " shift lines by 4 spaces for indent
+set shell=bash          " set bash as default terminal
 set showmatch           " show the matching part of the pair for [] {} & ()
 set softtabstop=4       " for easier backspacing the soft tabs
 set tabstop=4           " set tabs to have 4 spaces
+set timeoutlen=100      " reduce mapping & keycode delay for sanppy responses
 set tws=15x0            " set terminal windows size
+set updatetime=100      " reduce Vim default delay time from 4000ms to 100ms
+
+" allow backspacing over everthing in insert mode
+set backspace=indent,eol,start
+
+" auto-switch between case-sensitive & case-insensitive search
+set ignorecase
+set smartcase
 
 " split layout
 set splitbelow
@@ -66,9 +79,16 @@ nnoremap <C-H> <C-W><C-H>
 " code folding
 set foldmethod=indent
 set foldlevel=99
+
 " enable folding with spacebar
 nnoremap <space> za
 
+" prevents `ftplugin` to enforce the textwidth while editing commit msg
+au FileType gitcommit setlocal textwidth=0
+
+" highlight colour for search results
+highlight Search ctermbg=LightYellow ctermfg=DarkGrey
+
 " highlight unneccessary whitespaces
 highlight BadWhitespace ctermbg=yellow guibg=yellow
 au BufRead,BufNewFile *.py,*.pyw,*.c,*.h match
@@ -76,7 +96,7 @@ au BufRead,BufNewFile *.py,*.pyw,*.c,*.h match
 
 " hide colorcolumn in non-editor windows
 au FileType fugitive,help,qf setlocal nonumber colorcolumn=
-au BufEnter * if &ft == '' | setlocal nonumber colorcolumn= | endif
+au BufAdd * if &previewwindow | set nonumber colorcolumn= | endif
 
 " enable all Python syntax highlighting features
 let python_highlight_all=1
@@ -117,3 +137,9 @@ let g:ale_linters={ 'python': ['pylint'] }
 let g:ale_fixers={ 'python': ['yapf'] }
 let g:ale_open_list=1
 let g:ale_linters_explicit=1
+
+" plugin settings - vim-gitgutter
+highlight! link SignColumn LineNr
+highlight GitGutterAdd ctermfg=2
+highlight GitGutterChange ctermfg=3
+highlight GitGutterDelete ctermfg=1
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 88c728d..9b0ee8b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,37 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 
+## [2020.06.22]
+### Added
+- Auto case-sensitive & case-insensitive switch for searches
+- Vim plugin `airblade/vim-gitgutter` to show Git diff in the sign column next
+to line numbers in editor windows.
+- Vim plugin `Xuyuanp/nerdtree-git-plugin` to show Git status flags on NERDTree.
+- Highlight on search result & custom highlight colour.
+- Added global git config `credential.helper cache` for macOS user as
+`osxkeychain` is not available on Linux.
+
+### Changed
+- Default shell for Vim to `bash`.
+- Backspace to allow backspcaing over everthing in insert mode like most usual
+editors.
+- `cursorline` is now enabled by default.
+
+### Fixed
+- Heavy delay on shortcut `<<` while decreasing indent by reducing the
+`timeoutlen` to `100`(0.1s).
+- Text being moved to new line automatically at position `72` as Vim setting
+`textwidth` has been overriden by `ftplugin` for filetype `gitcomit.
+Implemented an `autocmd` to override it back to `textwidth=0`.
+- 1st file opened will notshow line numbers and colour column if Vim is
+initialised with cmd `vi`/`vim` due to the `autocmd` set to hide those items
+on `YouCompleteMe` preivew windo overrides the settings. Implemented a new
+`autocmd` which fixed this issue.
+
+### Removed
+- Vim plugin `jiangmiao/auto-pairs` as it somehow messes with the indents for
+bracket closures.
+
 ## [2020.06.19]
 ### Added
 - Vim plugin `dense-analysis/ale` (a.k.a. ALE) for much faster linting.
@@ -38,7 +69,8 @@ found` by pinning the `pipenv` version to `2018.11.26`.
 - `.vimrc` configured for Python developemnt.
 - Ubuntu 20.04 based dockerfiles to build images for Python 3.7 & 3.8 variants.
 
-[Unreleased]: https://github.com/devtography/pyvim/compare/2020.06.19...HEAD
+[Unreleased]: https://github.com/devtography/pyvim/compare/2020.06.22...HEAD
+[2020.06.22]: https://github.com/devtography/pyvim/compare/2020.06.19...2020.06.22
 [2020.06.19]: https://github.com/devtography/pyvim/compare/2020.06.18...2020.06.19
 [2020.06.18]: https://github.com/devtography/pyvim/compare/2020.06.17...2020.06.18
 [2020.06.17]: https://github.com/devtography/pyvim/releases/tag/2020.06.17
diff --git a/README.md b/README.md
index 98a6d05..1694358 100644
--- a/README.md
+++ b/README.md
@@ -9,13 +9,14 @@ development.
 Included Vim plugins:
 - [Vundle.vim] - plugins management
 - [NERDTree] - tree file explore
-- [NERD Commenter] - code comment
+- [nerdtree-git-plugin] - plugin of [NERDTree] showing git status flags
+- [NERD Commenter] - powerful code comment tool
 - [YouCompleteMe] - code completion
 - [SimpylFold] - cold folding for Python
 - [lightline.vim] - statusline/tabline
 - [fugitive.vim] - git integration
 - [Asynchronous Lint Engine] \(a.k.a. ALE) - linting
-- [auto-pairs] - auto generates surround pairs
+- [vim-gitgutter] - shows git diff in the sign column
 
 pyvim is good for remote Python development with iPad via `ssh`/`mosh` as 
 plugins & settings preconfigured in `.vimrc` are fully tested on the iPad 
@@ -52,13 +53,14 @@ pyvim is licensed under the [Apache License, Version 2.0](LICENSE.md).
 [Vim]: https://www.vim.org
 [Vundle.vim]: https://github.com/VundleVim/Vundle.vim
 [NERDTree]: https://github.com/preservim/nerdtree
+[nerdtree-git-plugin]: https://github.com/Xuyuanp/nerdtree-git-plugin
 [NERD Commenter]: https://github.com/preservim/nerdcommenter
 [YouCompleteMe]: https://github.com/ycm-core/YouCompleteMe
 [SimpylFold]: https://github.com/tmhedberg/SimpylFold
 [lightline.vim]: https://github.com/itchyny/lightline.vim 
 [fugitive.vim]: https://github.com/tpope/vim-fugitive
 [Asynchronous Lint Engine]: https://github.com/dense-analysis/ale
-[auto-pairs]: https://github.com/jiangmiao/auto-pairs
+[vim-gitgutter]: https://github.com/airblade/vim-gitgutter
 [Blink]: https://blink.sh
 [Vundle]: https://github.com/VundleVim/Vundle.vim
 [latest]: https://github.com/Devtography/pyvim/blob/master/docker/Dockerfile
diff --git a/docker/Dockerfile b/docker/Dockerfile
index f732428..24966c1 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -29,7 +29,8 @@ RUN apt-get install -y build-essential cmake curl git git-flow iputils-ping vim
     && git clone https://github.com/VundleVim/Vundle.vim.git \
     /root/.vim/bundle/Vundle.vim \
     && vim +PluginInstall +qall \
-    && /root/.vim/bundle/YouCompleteMe/install.py --clangd-completer
+    && /root/.vim/bundle/YouCompleteMe/install.py --clangd-completer \
+    && git config --global credentail.helper cache
 
 CMD ["bash"]
 
diff --git a/docker/Dockerfile_py3.7 b/docker/Dockerfile_py3.7
index 1a718e0..7bccc09 100644
--- a/docker/Dockerfile_py3.7
+++ b/docker/Dockerfile_py3.7
@@ -33,7 +33,8 @@ RUN apt-get install -y build-essential cmake curl git git-flow iputils-ping vim
     && git clone https://github.com/VundleVim/Vundle.vim.git \
     /root/.vim/bundle/Vundle.vim \
     && vim +PluginInstall +qall \
-    && /root/.vim/bundle/YouCompleteMe/install.py --clangd-completer
+    && /root/.vim/bundle/YouCompleteMe/install.py --clangd-completer \
+    && git config --global credential.helper cache
 
 CMD ["bash"]