For chutney, add all the ingredients (except oil, mustard, curry leaves & red chilli) in a mixer grinder and make a smooth / coarse paste by adding little amount of water.
Heat oil in a pan and add mustard. When it splutters, add curry leaves and red chillies; saute for a minute and season the chutney.
For Ragi Dosa, mix all the ingredients (except oil) and make a thin batter.
Heat a non stick dosa pan, drizzle some oil and pour the batter; first form an outer circle and then fill in the centre, just one layer. Again, drizzle some oil over it. Cook both the sides of dosa in a medium flame until the dosa turn brown in colour. Serve hot with coconut chutney.