added first few tests to verify providers

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
turn class constants into instance variables for providers

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
extracted login helper into separate module

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
provide first tests for LoginHelper

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
fixed minor print bug (get user variable)

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
print the username the user enters

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
add methods for setting oauth token and secret

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
feature: add configuration file

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
improvement: let bitbucket use oauth token and secret

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
bugfix: write configuration to file correctly

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
chomp user input

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
bugfix: abort oauth authentication if token is empty, not nil

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
bugfix: expand file path before writing

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>