Add GitHub links to DESCRIPTION

DESCRIPTION

+Package: ermoji
+Version: 0.1.0
+Title: RStudio Addin to Search and Copy Emoji
+Description: RStudio addin to search through emoji and copy the emoji name, 
+    unicode string or gliph to the clipboard.
+Authors@R: "Garrrick Aden-Buie <g.adenbuie@gmail.com> [aut, cre]"
+License: MIT
+Encoding: UTF-8
+LazyData: true
+ByteCompile: true
+Imports: 
+    emo,
+    DT,
+    purrr,
+    clipr
+Remotes: hadley/emo
+Depends: 
+    shiny,
+    miniUI
+Roxygen: list(markdown = TRUE)
+RoxygenNote: 6.0.1
+URL: https://github.com/gadenbuie/ermoji
+BugReports: https://github.com/gadenbuie/ermoji/issues