已知等差数列\(\{a_{n}\}\)的前\(n\)项和为\(S_{n}\)，且\(S_{5}=45\)，\(S_{6}=60\)．
\((\)Ⅰ\()\)求数列\(\{a_{n}\}\)的通项公式\(a_{n}\)；
\((\)Ⅱ\()\)若数列\(\{b_{n}\}\)满足\(b_{n+1}-b_{n}=a_{n}(n∈N*)\)，且\(b_{1}=3\)，求\(\{ \dfrac {1}{b_{n}}\}\)的前\(n\)项和\(T_{n}\)．