Add License

++The MIT License (MIT)
++
++Copyright (c) 2021 ParkJungMin, SeoJunHyuk, BaiHyungSeok
++
++Permission is hereby granted, free of charge, to any person obtaining a copy
++of this software and associated documentation files (the "Software"), to deal
++in the Software without restriction, including without limitation the rights
++to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
++copies of the Software, and to permit persons to whom the Software is
++furnished to do so, subject to the following conditions:
++
++The above copyright notice and this permission notice shall be included in all
++copies or substantial portions of the Software.
++
++THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
++IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
++FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
++AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
++LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
++OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
++SOFTWARE.
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