Add Discord Slash command documentation

slash_commands.md

@@ -0,0 +1,68 @@
+# Discord Slash Commands
+### `create_option()` and Command Types
+
+## `create_option()` Syntax
+```python
+create_option(name="something", description="Something else", option_type=3, required=True)
+```
+
+In this snippet, an example option `something` is provided here for reference.
+
+* name: The option's name
+* description: What the use of the option is, or what it does. Make sure it is understandable by all users
+* option_type: Can only be defined as an `int`. The argument type, whether it is a string, integer, user mention, channel, role, etc.
+* required: Whether the option has to be inputted by the user or not
+
+## What is Discord Slash Command types?
+Discord slash command types define what kind of argument is expected in a slash command.
+For example, if I wanted to restrict integers to an argument `number`, I would write the command like this:
+
+```python
+import discord
+from discord_slash import SlashCommand
+from discord_slash.utils.manage_commands import create_option
+client = discord.Client()
+slash = SlashCommand(client)
+@slash.slash(
+    name="some_command",
+    description="Does something",
+    options=[
+        create_option(name="number", description="Place to input a number", option_type=4, required=True)
+    ]
+)
+async def some_command(ctx, number):
+    await ctx.send(number + 1)
+```
+
+Here, see line 10. You can see in `create_option()` that the `option_type` argument was passed as a `4`. This is because 4 refers to an integer in the discord_slash library.
+
+However, you can also directly define it in the method itself.
+
+```python
+import discord
+from discord_slash import SlashCommand
+client = discord.Client()
+slash = SlashCommand(client)
+@slash.slash(
+    name="some_command",
+    description="Does something"
+)
+async def some_command(ctx, number:int):
+    await ctx.send(number + 1)
+```
+
+In this snippet, see line 9. In this example, the argument type was directly defined in the command itself. The discord_slash library reads this and automatically sets that as the slash command `option_type`. However, to avoid confusion, it is best to just define it in `create_option()`.
+
+## Some Option Types
+Not all option types are provided here, just the ones that will be used the most.
+
+* sub-command: 1
+* sub-command group: 2
+* string: 3
+* int: 4
+* bool: 5
+* user: 6
+* channel: 7
+* role: 8
+
+<h6>NKA 2022 | Py | Discord | discord_slash | Discord library documentation</h6>