SQLServer localdb is not availalble for Linux (and maybe Mac)

[tanaka-takayoshi]

Related to case #98
SQLite is available for Windows, Linux and Mac.
https://github.com/VenusInterns/BlogTemplate/blob/master/BlogTemplate/Startup.cs#L26

Like below.

services.AddDbContext<ApplicationDbContext>(options =>
                options.UseSqlite("Data Source=blogging.db"));