Find the tangent bundle

Question

I've got $\mathbb{R}$ and set $M=\mathbb{Q} \subset \mathbb{R}$. I need to find a tangent bundle $T_{x}M$ at any point $x\in\mathbb{Q}$. For given $M \subset X$ - normed space, $h \in X$ - tangent vector for $M$ at point $x$ if $\exists \varepsilon >0$ and the map $r(t)$, $t\in(-\varepsilon,\varepsilon)$ so that $x+th+r(t) \in M$ $\forall t\in(-\varepsilon,\varepsilon)$ and $\frac{\Vert r(t)\Vert}{t}\to0$. So if $h \in \mathbb{Q}$, it's still hard for me to understand how $r(t)$ should look... for irrational the same thing..