Add GPL3 header and github

.gitm.toml

@@ -1,3 +1,4 @@
 [repos]
 origin = "ssh://git@192.168.100.62:2222/Arsen6331/gitm.git"
 gitlab = "git@gitlab.com:moussaelianarsen/gitm.git"
+github = "git@github.com:Arsen6331/gitm.git"

gitm.rb

@@ -1,5 +1,22 @@
 #!/usr/bin/ruby
 
+# Gitm. Automatic git mirroring script.
+#
+# Copyright (C) 2021 Arsen Musayelyan <arsen@arsenm.dev>
+#
+# This program is free software: you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation, either version 3 of the License, or (at your option) any later
+# version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License along with
+# this program. If not, see <https://www.gnu.org/licenses/>.
+
+
 require 'toml'
 require 'colorize'
 
@@ -38,4 +55,4 @@ when "init"
   system "git checkout master"
 else
   system "git", *args
-end
+end