Missing license and the copyright info

[kalkayan]

Add Apache 2.0 license and add proper citations with the author's name, for example:-

# Copyright 2020 The DTU Times Authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# Author(s):         Manish Sahani <rec.manish.sahani@gmail.com>
#                    Name <email>

add the names of developers in the files that they have worked.

@ShivamSinghal1 @shivambansal0804