Added postgres support (#556)

Content.Server.Database/Configuration.cs

@@ -0,0 +1,70 @@
+using Microsoft.EntityFrameworkCore;
+using Npgsql;
+
+namespace Content.Server.Database
+{
+    public interface IDatabaseConfiguration
+    {
+        DbContextOptions<PreferencesDbContext> Options { get; }
+    }
+
+    public class PostgresConfiguration : IDatabaseConfiguration
+    {
+        private readonly string _database;
+        private readonly string _host;
+        private readonly string _password;
+        private readonly int _port;
+        private readonly string _username;
+
+        public PostgresConfiguration(string host,
+            int port,
+            string database,
+            string username,
+            string password)
+        {
+            _host = host;
+            _port = port;
+            _database = database;
+            _username = username;
+            _password = password;
+        }
+
+        public DbContextOptions<PreferencesDbContext> Options
+        {
+            get
+            {
+                var optionsBuilder = new DbContextOptionsBuilder<PreferencesDbContext>();
+                var connectionString = new NpgsqlConnectionStringBuilder
+                {
+                    Host = _host,
+                    Port = _port,
+                    Database = _database,
+                    Username = _username,
+                    Password = _password
+                }.ConnectionString;
+                optionsBuilder.UseNpgsql(connectionString);
+                return optionsBuilder.Options;
+            }
+        }
+    }
+
+    public class SqliteConfiguration : IDatabaseConfiguration
+    {
+        private readonly string _databaseFilePath;
+
+        public SqliteConfiguration(string databaseFilePath)
+        {
+            _databaseFilePath = databaseFilePath;
+        }
+
+        public DbContextOptions<PreferencesDbContext> Options
+        {
+            get
+            {
+                var optionsBuilder = new DbContextOptionsBuilder<PreferencesDbContext>();
+                optionsBuilder.UseSqlite($"Data Source={_databaseFilePath}");
+                return optionsBuilder.Options;
+            }
+        }
+    }
+}