title: Send a message when the bot joins a server
body: <p>I want to send a message everytime when the bot gets invited to a server. It should then write something like: "Hello this is my discord bot"</p>
  
  <p>So far I have this code, which produces no errors, but also doesn't send the message.</p>
  
  <pre><code>@bot.event
  async def on_server_join(ctx):
      for guild in bot.guilds:
          for channel in guild.text_channels:
              if channel.permissions_for(guild.me).say:
                  await ctx.message.channel.send('Hello! \n')
                  break
  </code></pre>