Imports of migrations command

PathSynopsis
contextPackage context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes.
fmtPackage fmt implements formatted I/O with functions analogous to C's printf and scanf.
github.com/google/go-github/v39/githubPackage github provides a client for using the GitHub API.
golang.org/x/oauth2Package oauth2 provides support for making OAuth2 authorized and authenticated HTTP requests, as specified in RFC 6749.