add my custom theme

.gitignore

 custom/*
+
+.DS_Store
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themes/l/fish_prompt.fish

+function _git_branch_name
+  echo (git symbolic-ref HEAD ^/dev/null | sed -e 's|^refs/heads/||')
+end
+
+function _is_git_dirty
+  echo (git status -s --ignore-submodules=dirty ^/dev/null)
+end
+
+function fish_prompt
+  set -l blue (set_color blue)
+  set -l green (set_color green)
+  set -l normal (set_color normal)
+
+  set -l arrow "λ"
+  set -l cwd $blue(basename (prompt_pwd))
+
+  if [ (_git_branch_name) ]
+    set git_info $green(_git_branch_name)
+    set git_info ":$git_info"
+
+    if [ (_is_git_dirty) ]
+      set -l dirty "*"
+      set git_info "$git_info$dirty"
+    end
+  end
+
+  echo -n -s $cwd $git_info $normal ' ' $arrow ' '
+end
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