Use a local SQLite3 backend instead of PostgreSQL Docker container.

* The provided SQLite3 database contains the required schemas, but no data and can be reset to if required.
* Remove all references to PostgreSQL in documentation and configuration.
* Replace native sqlite3 command with a console app to remove dependency on SQLite3 installation.

show-posts/Post.cs

@@ -0,0 +1,24 @@
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+
+[Table("posts")]
+public class Post
+{
+    [Key]
+    [Column("id")]
+    public int Id { get; set; }
+
+    [Column("user_id")]
+    public int UserId { get; set; }
+
+    [Column("title")]
+    [Required]
+    public string Title { get; set; } = string.Empty;
+
+    [Column("body")]
+    [Required]
+    public string Body { get; set; } = string.Empty;
+
+    [Column("updated_at")]
+    public DateTimeOffset UpdatedAt { get; set; } = DateTimeOffset.Parse("1970-01-01T00:00:00Z"); // TODO: Remove the default value in Phase 3.
+}

show-posts/PostsDbContext.cs

@@ -0,0 +1,20 @@
+using Microsoft.EntityFrameworkCore;
+
+public class PostsDbContext : DbContext
+{
+    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
+    {
+        var currentDir = System.IO.Directory.GetCurrentDirectory();
+        int showPostsIndex = currentDir.IndexOf("show-posts");
+        if (showPostsIndex > -1)
+        {
+            // Running from the bin directory, get the parent of "show-posts".
+            currentDir = currentDir.Substring(0, showPostsIndex - 1);
+        }
+        string repoRoot = currentDir;
+
+        optionsBuilder.UseSqlite($"Data Source={repoRoot}/service/service.db;Mode=ReadOnly;");
+    }
+
+    public DbSet<Post> Posts { get; set; }
+}

show-posts/Program.cs

@@ -0,0 +1,4 @@
+using table.lib;
+
+using var context = new PostsDbContext();
+Table<Post>.Add(context.Posts.ToList()).ToConsole();

show-posts/show-posts.csproj

@@ -0,0 +1,17 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <RootNamespace>show_posts</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="9.0.13" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="9.0.13" />
+    <PackageReference Include="table.lib" Version="1.17.0" />
+  </ItemGroup>
+
+</Project>