Add sendMsg function to channel class

This function implements sending messages to all users in a channel
while sending the channel name as target to the user's socket.

src/channel.js

@@ -20,6 +20,13 @@ function Channel(name) {
           this.userlist.splice(index, 1)
       }
   }
+
+  this.sendMsg = function(from, message) {
+      const channel = this
+      this.userlist.forEach(function(item) {
+          item.sendMsg(from, message, channel.name)
+      })
+  }
 }
 
 module.exports = Channel

test/channel.js

@@ -38,4 +38,21 @@ describe('Channel', function () {
             channel.part(mockedUser)
         })
     })
+
+    describe('#sendMsg(from, message)', function () {
+        it("should remove a user from a channel and send a PART command to the user", function (done) {
+            const channel = new Channel("#testchan")
+            let mockedUser = {nickname: "some_nick", sendRaw: function() {}}
+            mockedUser.sendMsg = function(from, message, to) {
+                assert.equal(from, mockedUser)
+                assert.equal(message, "test message")
+                assert.equal(to, "#testchan")
+                done()
+            }
+            // we can't part a channel without joining it first
+            channel.join(mockedUser)
+
+            channel.sendMsg(mockedUser, "test message")
+        })
+    })
 })