Add Timestamp Column to Proposals Table

Info: The 'created_at' column already exists in the proposals table.
Current Proposals Table Structure:
Field Type Null Key Default Extra
idint(11)NOPRINULLauto_increment
full_namevarchar(255)NONULL
programme_of_studyvarchar(255)NONULL
levelvarchar(50)NONULL
contactvarchar(15)NONULL
emailvarchar(255)NONULL
business_idea_titlevarchar(255)NONULL
brief_descriptiontextNONULL
target_markettextNONULL
competitorstextNONULL
market_trendstextNONULL
initial_capitalvarchar(50)NONULL
required_resourcestextNONULL
skills_neededtextYESNULL
potential_partnershipstextYESNULL
social_impacttextYESNULL
technological_elementstextYESNULL
member1_namevarchar(255)YESNULL
member1_programmevarchar(255)YESNULL
member1_levelvarchar(50)YESNULL
member1_emailvarchar(255)YESNULL
member2_namevarchar(255)YESNULL
member2_programmevarchar(255)YESNULL
member2_levelvarchar(50)YESNULL
member2_emailvarchar(255)YESNULL
created_attimestampYEScurrent_timestamp()