How to add a ruble sign to an existing font?

Question

Fonts

Hello.
I want to expand my favorite Roboto font, add a ruble sign there. I'm using Fontlab Studio 5. I want to add a character exactly to U+20bd. If you open .ttf, then this range is not in the font. How can I add a new Unicode code in this application?
In fact, it does not matter in which tool to do this, if you know another way - say.

Answer 1

load the font at the
bottom unicode - ranges mode - Currency Symbols
for the ruble code 20bd
we take the glyph of the letter P-Russian (sometimes it differs from the English P) but this is already a frills .. and finish drawing the vector drawing. see the lessons if you don’t know how
for the robot font all this is not needed. there already seems to be this symbol in it.
but for others it might be useful.