Add fish script for helping with rebasing of post_* tags

scripts/rebase.fish

@@ -0,0 +1,29 @@
+git fetch --tags
+
+for x in (seq 1000)
+	set n (math $x + 1)
+	if not git checkout post_$n 2> /dev/null
+		if git checkout post_{$x}_new 2> /dev/null
+			git tag -f post_$x post_{$x}_new
+			git tag -d post_{$x}_new
+			git push origin post_$x --force
+		end
+		break
+	end
+
+	if git checkout post_{$x}_new 2> /dev/null
+		echo \nrebasing post_$n on top of post_{$x}_new\n--------------------------------------
+		if git checkout post_{$n}_new 2> /dev/null
+			echo Error: Multiple post_n_new tags!
+			exit 1
+		end
+		if not git rebase --onto post_{$x}_new post_$x post_$n
+			exit 1
+		end
+
+		git tag post_{$n}_new HEAD
+		git tag -f post_$x post_{$x}_new
+		git tag -d post_{$x}_new
+		git push origin post_$x --force
+	end
+end