modify neovim, update-alternatives at hooks

neovim-bin/DEBBUILD

@@ -2,7 +2,7 @@
 
 pkgname="neovim"
 pkgver="0.9.0"
-pkgrel=4
+pkgrel=5
 pkgcommit=""
 pkgdesc="A modern editor"
 url="https://github.com/neovim/neovim"
@@ -18,3 +18,15 @@ function package {
     mv "${srcdir}/nvim-linux64/lib" "${pkgdir}/usr/lib"
     mv "${srcdir}/nvim-linux64/share" "${pkgdir}/usr/share"
 }
+
+function debian_postinst {
+cat << EOF
+update-alternatives --install /usr/bin/editor editor /usr/bin/nvim 80
+EOF
+}
+
+function debian_prerm {
+cat << EOF
+update-alternatives --remove editor /usr/bin/nvim
+EOF
+}