Add documentation for Preconditions, Aliases, Command Structure

Resolves #223

docs/guides/samples/groups.cs

@@ -0,0 +1,15 @@
+[Module("admin")]
+public class AdminModule
+{
+    [Group("mod")]
+    public class ModerationGroup
+    {
+        // ~admin mod ban foxbot#0282
+        [Command("ban")]
+        public async Task Ban(IMessage msg, IGuildUser user) { }
+    }
+
+    // ~admin clean 100
+    [Command("clean")]
+    public async Task Clean(IMessage msg, int count = 100) { }
+}

docs/guides/samples/module.cs

@@ -31,7 +31,9 @@ public class Sample
 	// ~sample userinfo Khionu#8708 --> Khionu#8708
 	// ~sample userinfo Khionu --> Khionu#8708
 	// ~sample userinfo 96642168176807936 --> Khionu#8708
+    // ~sample whois 96642168176807936 --> Khionu#8708
 	[Command("userinfo"), Description("Returns info about the current user, or the user parameter, if one passed.")]
+    [Alias("user", "whois")]
     public async Task UserInfo(IMessage msg,
         [Description("The (optional) user to get info for")] IUser user = null)
     {

docs/guides/samples/require_context.cs

@@ -0,0 +1,11 @@
+[Module]
+public class InfoModule
+{
+    // Constrain this command to Guilds
+    [RequireContext(ContextType.Guild)]
+    public async Task Whois(IMessage msg, IGuildUser user) { }
+
+    // Constrain this command to either Guilds or DMs
+    [RequireContext(ContextType.Guild | ContextType.DM)]
+    public async Task Info(IMessage msg) { }
+}

docs/guides/samples/require_owner.cs

@@ -0,0 +1,16 @@
+// Defining the Precondition
+
+// Specify that this precondition can target a Class (Module/Group) or Method (Command)
+[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
+// Inherit from PreconditionAttribute
+public class RequireOwnerAttribute : PreconditionAttribute
+{
+    public readonly ulong OwnerId = 66078337084162048;
+
+    // Override the CheckPermissions method
+    public override Task<PreconditionResult> CheckPermissions(IMessage context, Command executingCommand, object moduleInstance)
+    {
+        // If the author of the message is '66078337084162048', return success; otherwise fail. 
+        return Task.FromResult(context.Author.Id == OwnerId ? PreconditionResult.FromSuccess() : PreconditionResult.FromError("You must be the owner of the bot."));
+    }
+}

docs/guides/samples/require_permission.cs

@@ -0,0 +1,7 @@
+[Module]
+public class AdminModule
+{
+    [Command("ban")]
+    [RequirePermission(GuildPermission.BanMembers)]
+    public async Task Ban(IMessage msg) { }
+}